A shop sells a particular of video recorder. Assuming that the weekly demand for the video recorder is a Poisson variable with the mean 3, find the probability that the shop sells. . (a) At least 3 in a week. (b) At most 7 in a week. (c) More than 20 in a month (4 weeks).

Answers

Answer 1

Answer:

a) 0.5768 = 57.68% probability that the shop sells at least 3 in a week.

b) 0.988 = 98.8% probability that the shop sells at most 7 in a week.

c) 0.0104 = 1.04% probability that the shop sells more than 20 in a month.

Step-by-step explanation:

For questions a and b, the Poisson distribution is used, while for question c, the normal approximation is used.

Poisson distribution:

In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

[tex]P(X = x) = \frac{e^{-\lambda}*\lambda^{x}}{(x)!}[/tex]

In which

x is the number of successes

e = 2.71828 is the Euler number

[tex]\lambda[/tex] is the mean in the given interval.

Normal Probability Distribution

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

The Poisson distribution can be approximated to the normal with [tex]\mu = \lambda, \sigma = \sqrt{\lambda}[/tex], if [tex]\lambda>10[/tex].

Poisson variable with the mean 3

This means that [tex]\lambda= 3[/tex].

(a) At least 3 in a week.

This is [tex]P(X \geq 3)[/tex]. So

[tex]P(X \geq 3) = 1 - P(X < 3)[/tex]

In which:

[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]

Then

[tex]P(X = x) = \frac{e^{-\lambda}*\lambda^{x}}{(x)!}[/tex]

[tex]P(X = 0) = \frac{e^{-3}*3^{0}}{(0)!} = 0.0498[/tex]

[tex]P(X = 1) = \frac{e^{-3}*3^{1}}{(1)!} = 0.1494[/tex]

[tex]P(X = 2) = \frac{e^{-3}*3^{2}}{(2)!} = 0.2240[/tex]

So

[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0498 + 0.1494 + 0.2240 = 0.4232[/tex]

[tex]P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 1 - 0.4232 = 0.5768[/tex]

0.5768 = 57.68% probability that the shop sells at least 3 in a week.

(b) At most 7 in a week.

This is:

[tex]P(X \leq 7) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7)[/tex]

In which

[tex]P(X = x) = \frac{e^{-\lambda}*\lambda^{x}}{(x)!}[/tex]

[tex]P(X = 0) = \frac{e^{-3}*3^{0}}{(0)!} = 0.0498[/tex]

[tex]P(X = 1) = \frac{e^{-3}*3^{1}}{(1)!} = 0.1494[/tex]

[tex]P(X = 2) = \frac{e^{-3}*3^{2}}{(2)!} = 0.2240[/tex]

[tex]P(X = 3) = \frac{e^{-3}*3^{3}}{(3)!} = 0.2240[/tex]

[tex]P(X = 4) = \frac{e^{-3}*3^{4}}{(4)!} = 0.1680[/tex]

[tex]P(X = 5) = \frac{e^{-3}*3^{5}}{(5)!} = 0.1008[/tex]

[tex]P(X = 6) = \frac{e^{-3}*3^{6}}{(6)!} = 0.0504[/tex]

[tex]P(X = 7) = \frac{e^{-3}*3^{7}}{(7)!} = 0.0216[/tex]

Then

[tex]P(X \leq 7) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) = 0.0498 + 0.1494 + 0.2240 + 0.2240 + 0.1680 + 0.1008 + 0.0504 + 0.0216 = 0.988[/tex]

0.988 = 98.8% probability that the shop sells at most 7 in a week.

(c) More than 20 in a month (4 weeks).

4 weeks, so:

[tex]\mu = \lambda = 4(3) = 12[/tex]

[tex]\sigma = \sqrt{\lambda} = \sqrt{12}[/tex]

The probability, using continuity correction, is P(X > 20 + 0.5) = P(X > 20.5), which is 1 subtracted by the p-value of Z when X = 20.5.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{20 - 12}{\sqrt{12}}[/tex]

[tex]Z = 2.31[/tex]

[tex]Z = 2.31[/tex] has a p-value of 0.9896.

1 - 0.9896 = 0.0104

0.0104 = 1.04% probability that the shop sells more than 20 in a month.

Answer 2

The probability of the selling the video recorders for considered cases are:

P(At least 3 in a week) = 0.5768 approximately.P(At most 7 in a week) = 0.9881 approximately.P( more than 20 in a month) = 0.0839 approximately.

What are some of the properties of Poisson distribution?

Let X ~ Pois(λ)

Then we have:

E(X) = λ = Var(X)

Since standard deviation is square root (positive) of variance,

Thus,

Standard deviation of X = [tex]\sqrt{\lambda}[/tex]

Its probability function is given by

f(k; λ) = Pr(X = k) = [tex]\dfrac{\lambda^{k}e^{-\lambda}}{k!}[/tex]

For this case, let we have:

X = the number of weekly demand of video recorder for the considered shop.

Then, by the given data, we have:

X ~ Pois(λ=3)


Evaluating each event's probability:

Case 1: At least 3 in a week.

[tex]P(X > 3) = 1- P(X \leq 2) = \sum_{i=0}^{2}P(X=i) = \sum_{i=0}^{2} \dfrac{3^ie^{-3}}{i!}\\\\P(X > 3) = 1 - e^{-3} \times \left( 1 + 3 + 9/2\right) \approx 1 - 0.4232 = 0.5768[/tex]

Case 2: At most 7 in a week.

[tex]P(X \leq 7) = \sum_{i=0}^{7}P(X=i) = \sum_{i=0}^{7} \dfrac{3^ie^{-3}}{i!}\\\\P(X \leq 7) = e^{-3} \times \left( 1 + 3 + 9/2 + 27/6 + 81/24 + 243/120 + 729/720 + 2187/5040\right)\\\\P(X \leq 7) \approx 0.9881[/tex]

Case 3: More than 20 in a month(4 weeks)

That means more than 5 in a week on average.

[tex]P(X > 5) = 1- P(X \leq 5) =\sum_{i=0}^{5}P(X=i) = \sum_{i=0}^{5} \dfrac{3^ie^{-3}}{i!}\\\\P(X > 5) = 1- e^{-3}( 1 + 3 + 9/2 + 27/6 + 81/24 + 243/120)\\\\P(X > 5) \approx 1 - 0.9161 \\ P(X > 5) \approx 0.0839[/tex]


Thus, the probability of the selling the video recorders for considered cases are:

P(At least 3 in a week) = 0.5768 approximately.P(At most 7 in a week) = 0.9881 approximately.P( more than 20 in a month) = 0.0839 approximately.

Learn more about poisson distribution here:

https://brainly.com/question/7879375


Related Questions

Estimate the average rate of change from x 1 to x = 4. Enter your estimate as a decimal number (not as a fraction), rounded to one decimal place. Average rate of change = Number​

Answers

Answer:Mark brainliest please

Answer is - 0.5

Step-by-step explanation:

The average rate of change is -0.5 which is the average rate of change from x 1 to x = 4 the answer is -0.5.

What is the rate of change?

It is defined as the change in values of a dependent variable with respect to the independent variables.

As we know an average is a single number that represents the mean value for the given set of data or the closed value for each entry given in the set of data.

We have a graph of functions shown in the picture.

Estimate the average rate of change from x 1 to x = 4.

At x = 1,

y = 5

At x = 4

y = 3.5(approx)

The average rate of change = (3.5 - 5)/(4 - 1)

The average rate of change = -1.5/3

The average rate of change = -0.5

Thus, the average rate of change is -0.5 which is the average rate of change from x 1 to x = 4 the answer is -0.5.

Learn more about the rate of change here:

brainly.com/question/12786410

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Calculus II Question

Identify the function represented by the following power series.

[tex]\sum_{k = 0}^\infty (-1)^k \frac{x^{k + 2}}{4^k}[/tex]

Answers

With some rewriting, you get

[tex]\displaystyle \sum_{k=0}^\infty (-1)^k\frac{x^{k+2}}{4^k} = x^2 \sum_{k=0}^\infty \left(-\frac x4\right)^k[/tex]

Recall that for |x| < 1, you have

[tex]\displaystyle \frac1{1-x} = \sum_{k=0}^\infty x^k[/tex]

So as long as |-x/4| = |x/4| < 1, or |x| < 4, your series converges to

[tex]\displaystyle x^2 \sum_{k=0}^\infty \left(-\frac x4\right)^k = \frac{x^2}{1-\left(-\frac x4\right)} = \frac{x^2}{1+\frac x4} = \boxed{\frac{4x^2}{4+x}}[/tex]

Based on known expressions from Taylor series, the power series [tex]\sum \limits_{k = 0}^{\infty} (-1)^{k}\cdot \frac{x^{k+2}}{4^{k}}[/tex]Taylor series-derived formula of the rational function [tex]\frac{4\cdot x^{2}}{4+x}[/tex].

How to derive a function behind the approximated formula by Taylor series

Taylor series are polynomic approximations used to estimate values both from trascendental and non-trascendental functions. It is commonly used in trigonometric, potential, logarithmic and even rational functions.

In this question we must use series properties and common Taylor series-derived formulas to infer the expression behind the given series. Now we proceed to find the expression:

[tex]\sum \limits_{k = 0}^{\infty} (-1)^{k}\cdot \frac{x^{k+2}}{4^{k}}[/tex]

[tex]x^{2}\cdot \sum\limits_{k = 0}^{\infty} \left(-\frac{x}{4} \right)^{k}[/tex]

[tex]x^{2}\cdot \left(\frac{1}{1+\frac{x}{4} } \right)[/tex]

[tex]\frac{4\cdot x^{2}}{4+x}[/tex]

Based on power and series properties and most common Taylor series- derived formulas, the power series [tex]\sum \limits_{k = 0}^{\infty} (-1)^{k}\cdot \frac{x^{k+2}}{4^{k}}[/tex] represents a Taylor series-derived formula of the rational function [tex]\frac{4\cdot x^{2}}{4+x}[/tex]. [tex]\blacksquare[/tex]

To learn more on Taylor series, we kindly invite to check this verified question: https://brainly.com/question/12800011

If JKL = TUV which of the following can you not conclude as being true

Answers

Answer:

Step-by-step explanation:

D

Answer:

J ≅ V

Step-by-step explanation: I took the same test (:

Find the value of x on this triangle

Answers

Answer:

x = 35

Step-by-step explanation:

We can use the Pythagorean theorem since this is a right triangle

a^2 + b^2 = c^2  where a and b are the legs and c is the hypotenuse

x^2 + 12^2 = (x+2)^2

FOIL

x^2+144=x^2+4x+4

Subtract x^2 from each side

144= 4x+4

Subtract 4 from each side

140 = 4x

Divide by 4

35 =x

The number of defective circuit boards coming off a soldering machine follows a Poisson distribution. During a specific ten-hour period, one defective circuit board was found. (a) Find the probability that it was produced during the first hour of operation during that period. (Round your answer to four decimal places.) (b) Find the probability that it was produced during the last hour of operation during that period. (Round your answer to four decimal places.) (c) Given that no defective circuit boards were produced during the first five hours of operation, find the probability that the defective board was manufactured during the sixth hour. (Round your answer to four decimal places.)

Answers

Answer:

a) the probability that the defective board was produced during the first hour of operation is [tex]\frac{1}{10}[/tex] or 0.1000

b) the probability that the defective board was produced during the  last hour of operation is [tex]\frac{1}{10}[/tex] or 0.1000

c) the required probability is 0.2000

Step-by-step explanation:

Given the data in the question;

During a specific ten-hour period, one defective circuit board was found.

Lets X represent the number of defective circuit boards coming out of the machine , following Poisson distribution on a particular 10-hours workday which one defective board was found.

Also let Y represent the event of producing one defective circuit board, Y is uniformly distributed over ( 0, 10 ) intervals.

f(y) = [tex]\left \{ {{\frac{1}{b-a} }\\\ }} \right _0[/tex];   ( a ≤ y ≤ b )[tex]_{elsewhere[/tex]

= [tex]\left \{ {{\frac{1}{10-0} }\\\ }} \right _0[/tex];   ( 0 ≤ y ≤ 10 )[tex]_{elsewhere[/tex]

f(y) = [tex]\left \{ {{\frac{1}{10} }\\\ }} \right _0[/tex];   ( 0 ≤ y ≤ 10 )[tex]_{elsewhere[/tex]

Now,

a) the probability that it was produced during the first hour of operation during that period;

P( Y < 1 )   =   [tex]\int\limits^1_0 {f(y)} \, dy[/tex]

we substitute

=    [tex]\int\limits^1_0 {\frac{1}{10} } \, dy[/tex]

= [tex]\frac{1}{10} [y]^1_0[/tex]

= [tex]\frac{1}{10} [ 1 - 0 ][/tex]

= [tex]\frac{1}{10}[/tex] or 0.1000

Therefore, the probability that the defective board was produced during the first hour of operation is [tex]\frac{1}{10}[/tex] or 0.1000

b) The probability that it was produced during the last hour of operation during that period.

P( Y > 9 ) =    [tex]\int\limits^{10}_9 {f(y)} \, dy[/tex]

we substitute

=    [tex]\int\limits^{10}_9 {\frac{1}{10} } \, dy[/tex]

= [tex]\frac{1}{10} [y]^{10}_9[/tex]

= [tex]\frac{1}{10} [ 10 - 9 ][/tex]

= [tex]\frac{1}{10}[/tex] or 0.1000

Therefore, the probability that the defective board was produced during the  last hour of operation is [tex]\frac{1}{10}[/tex] or 0.1000

c)

no defective circuit boards were produced during the first five hours of operation.

probability that the defective board was manufactured during the sixth hour will be;

P( 5 < Y < 6 | Y > 5 ) = P[ ( 5 < Y < 6 ) ∩ ( Y > 5 ) ] / P( Y > 5 )

= P( 5 < Y < 6 ) / P( Y > 5 )

we substitute

 [tex]= (\int\limits^{6}_5 {\frac{1}{10} } \, dy) / (\int\limits^{10}_5 {\frac{1}{10} } \, dy)[/tex]

[tex]= (\frac{1}{10} [y]^{6}_5) / (\frac{1}{10} [y]^{10}_5)[/tex]

= ( 6-5 ) / ( 10 - 5 )

= 0.2000

Therefore, the required probability is 0.2000

Question Which of the following is a benefit of using email to communicate at work ? a) You can express yourself in a limited number of characters b) You don't have to worry about using proper grammar. c) You always get a response right away. d ) You can reach a large audience with one communication .

Answers

Answer:

d) you can reach a large audience with one communication

Step-by-step explanation:

common sense

There is a path of width 2.5 m inside around a square garden of length 45m.
(a) Find the area of the path.
(b) How many tiles will be required to pave in the path by the square tiles of length 0.5m? Find it.

Help ! 도와주세요, 제발 :(​

Answers

Answer:

2.5+2.5+45+45

=95.0m

therefore area of the square= 95.0m

45m×0.5=45.5÷95=

Step-by-step explanation:

2.5m

2.5 m tiles are required

[tex]area = 2.5 \times 45 = 192.5 \: squared \: cenimetre \\ \\ no \: of \: tiles = 0.5 \times 0.5 = 0.25 \\ 192.5 \div 0.25 = 770tiles[/tex]

a figure skating school offers introductory lessons at $25 per session. There is also a registration fee of $30

Answers

Answer:

Part A: y = 25x + 30

Part B: $180

Step-by-step explanation:

for part A, 25 is the constant so that goes with the x, and you just add 30 because it is the extra fee. slope intercept form is y = mx + b

for part B you just plug 6 into the slope intercept equation

y = 25(6) + 30

y = 150 + 30

y = 180

$180

the perimeter of a square is less than or equal to 50 find the range of the value of the length of the square​

Answers

Answer:

12.5  ≥ s >0

Step-by-step explanation:

The perimeter of a square is given by

P = 4s where s is the side length

50 ≥ 4s

Divide each side by 4

50/4 ≥ 4s/4

25/2  ≥ s

12.5  ≥ s

A 40-foot tree casts a shadow 60 feet long. How long would the shadow of a 6-foot man be at that time?​

Answers

Answer:

26 ft

Step-by-step explanation:

I'm guessing this is how it's done

60-40= 20

there for at this time any shadow would be 20x it's original height/length

so 6+20=26 ft

lmk if I'm correct

Taking ratios

Let the shadow length=x ft

[tex]\\ \sf\longmapsto 40:60=6:x[/tex]

[tex]\\ \sf\longmapsto \dfrac{40}{60}=\dfrac{6}{x}[/tex]

[tex]\\ \sf\longmapsto \dfrac{4}{6}=\dfrac{6}{x}[/tex]

[tex]\\ \sf\longmapsto 4x=6(6)[/tex]

[tex]\\ \sf\longmapsto 4x=36[/tex]

[tex]\\ \sf\longmapsto x=\dfrac{36}{4}[/tex]

[tex]\\ \sf\longmapsto x=9[/tex]

need help asap :) ty

Answers

Answer:

3:7

Step-by-step explanation:

i hope this helps

What is the surface area of a cube with a side length of 6 m?
156 m2
300 m2
216 m2
360 m2

Answers

Answer:

216 m²

Step-by-step explanation:

Surface area of a cube = 6a², when a = length of one side

so,

6a²

= 6×6²

= 6×36

= 216 m²

Answered by GAUTHMATH

Answer:

216 m²

Step-by-step explanation:

Find the range for the following data 14, 16, 16, 14, 22, 13, 15, 24, 12, 23, 14, 20, 17, 21, 22, 18, 18, 19, 20, 17, 16, 15, 11, 12, 21, 20, 17, 18, 19, 23

Answers

Answer:

12

Step-by-step explanation:

Range is the subtraction of the largest number and the smallest number.

The largest number is: 23

The smallest number is: 11

Now subtract:

23 - 11 = 12

Hope this helped.

Answer:

the lowest is 11 and the highest is 24 then subtract it you are going to have 13

Find the area of the shaded regions.

Answers

Answer:

around 22, or 21.98

Step-by-step explanation:

[tex]s1 = {r}^{2} \times \pi = 9 \times 3.14 = 28.26[/tex]

[tex]s2 = 1 \times 3.14 = 3.14[/tex]

[tex]s3 = 28.26 - (3.14 \times 2) = 28.26 - 6.28 = 21.98[/tex]

trong một thùng có chứa 3 bi đỏ 4 bi đen

Answers

Answer:

The FitnessGram™ Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. [beep] A single lap should be completed each time you hear this sound. [ding] Remember to run in a straight line, and run as long as possible. The second time you fail to complete a lap before the sound, your test is over.ep explanation:

Use the information below to complete the problem: p(x)=1/x+1 and q(x)=1/x-1 Perform the operation and show that it results in another rational expression. p(x) + q(x)

Answers

Answer:

hope u will understand...if u like this answer plz mark as brainlist

Answer:

[tex]\displaystyle p(x) + q(x) = \frac{2x}{(x+1)(x-1)}[/tex]

The result is indeed another rational expression.

Step-by-step explanation:

We are given the two functions:

[tex]\displaystyle p(x) = \frac{1}{x+1}\text{ and } q(x) = \frac{1}{x-1}[/tex]

And we want to perform the operation:

[tex]\displaystyle p(x) + q(x)[/tex]

And show that the result is another rational expression.

Add:

[tex]\displaystyle = \frac{1}{x+1} + \frac{1}{x-1}[/tex]

To combine the fractions, we will need a common denominator. So, we can multiply the first fraction by (x - 1) and the second by (x + 1):

[tex]\displaystyle = \frac{1}{x+1}\left(\frac{x-1}{x-1}\right) + \frac{1}{x-1}\left(\frac{x+1}{x+1}\right)[/tex]

Simplify:

[tex]=\displaystyle \frac{x-1}{(x+1)(x-1)} + \frac{x+1}{(x+1)(x-1)}[/tex]

Add:

[tex]\displaystyle = \frac{(x-1)+(x+1)}{(x+1)(x-1)}[/tex]

Simplify. Hence:

[tex]\displaystyle p(x) + q(x) = \frac{2x}{(x+1)(x-1)}[/tex]

The result is indeed another rational expression.

Write the equation of the line in fully simplified slope-intercept form.

Answers

Answer:

y = 6/5x-1

Step-by-step explanation:

We have two points so we can find the slope

(-5,-7) and (5,5)

The slope is

m = ( y2-y1)/(x2-x1)

   = ( 5- -7)/( 5 - -5)

   = (5+7)/(5+5)

    = 12/10

   = 6/5

The slope intercept form of a line is

y = mx+b

y = 6/5x+b

Using the point (5,5)

5 = 6/5(5)+b

5=6+b

b=-1

y = 6/5x-1

Plz someone help me

Answers

Step-by-step explanation:

yo

so sorry I can't

really answer it

find the LCM of 210, 280, 360 by prime factorisation​

Answers

Answer:

Step-by-step explanation:

210=2x3x5x7

280=2x2x2x5x7

360=2x2x2x3x3x5

Answer:

210= 2×3×5×7

280=2×2×2×5×7

360=2×2×2×3×3×5

common factors=2×2×2×3×5×7=840

uncommon factors=3

L.C.M=Common factors× uncommon factors

L.C.M=840×3

L.C.M=2520

Step-by-step explanation:

i hope it will be helpful

plzz mark as brainliest

5
13


The probabilities that three men win their respective races are 1/3,3/5and 3/4.what is theprobability that
a) all of them win their races)
b) only one of them win his race?

Answers

Answer:

a

Step-by-step explanation:

1/3 x 3/5 x 3/4 =7/12 so therefore that's what the answer isn't

Land surveyors outlined a park as shown. What is the area of the park?

Answers

la cuadra se llama 6minutos

I need help ASAP please and thank you

Answers

Answer:

"a" is the answer because 3x+2 can not be equal to zero

Step-by-step explanation:

somebody help me please​

Answers

Answer:

115

Step-by-step explanation:

Since the lines are parallel, PWX+WXR=180, WXR=65. So PWX=(180-65)=115

Use the following information to answer the next six exercises. There are 23 countries in North America, 12 countries in South America, 47 countries in Europe, 44 countries in Asia, 54 countries in Africa, and 14 in Oceania (Pacific Ocean region).
Let A = the event that a country is in Asia.
Let E = the event that a country is in Europe.
Let F = the event that a country is in Africa.
Let N = the event that a country is in North America. Let O = the event that a country is in Oceania.
Let S = the event that a country is in South America.
18. What is the probability of drawing a red card in a standard deck of 52 cards?
19. What is the probability of drawing a club in a standard deck of 52 cards?

Answers

The probabilities we found in this exercise are.

0.2268 = 22.68% probability that a country is in Asia.0.2423 = 24.23% probability that a country is in Europe.0.2784 = 27.84% probability that a country is in Africa.0.1186 = 11.86% probability that a country is in North America.0.0722 = 7.22% probability that a country is in Oceania.0.0619 = 6.19% probability that a country is in South America.0.5 = 50% probability of drawing a red card in a standard deck of 52 cards.0.25 = 25% probability of drawing a club in a standard deck of 52 cards.

In this exercise, probability concepts are used.

A probability is the number of desired outcomes divided by the number of total outcomes.

Total number of countries:

23 + 12 + 47 + 44 + 54 + 14 = 194

Let A = the event that a country is in Asia.

44 of the 194 countries are in Asia, thus:

[tex]P(A) = \frac{44}{194} = 0.2268[/tex]

0.2268 = 22.68% probability that a country is in Asia.

Let E = the event that a country is in Europe.

47 out of 194 countries are in Europe, thus:

[tex]P(E) = \frac{47}{194} = 0.2423[/tex]

0.2423 = 24.23% probability that a country is in Europe.

Let F = the event that a country is in Africa.

54 out of 194 countries are in Africa, thus:

[tex]P(F) = \frac{54}{194} = 0.2784[/tex]

0.2784 = 27.84% probability that a country is in Africa.

Let N = the event that a country is in North America.

23 out of 194 countries are in North America, thus:

[tex]P(N) = \frac{23}{194} = 0.1186[/tex]

0.1186 = 11.86% probability that a country is in North America.

Let O = the event that a country is in Oceania.

14 out of 194 countries are in Oceania, thus:

[tex]P(O) = \frac{14}{194} = 0.0722[/tex]

0.0722 = 7.22% probability that a country is in Oceania.

Let S = the event that a country is in South America.

12 out of 194 countries are in South America, thus:

[tex]P(S) = \frac{12}{194} = 0.0619[/tex]

0.0619 = 6.19% probability that a country is in South America.

18. What is the probability of drawing a red card in a standard deck of 52 cards?

In a standard deck of 52 cards, 26 are red, and thus:

[tex]p = \frac{26}{52} = 0.5[/tex]

0.5 = 50% probability of drawing a red card in a standard deck of 52 cards.

19. What is the probability of drawing a club in a standard deck of 52 cards?

In a standard deck of 52 cards, 13 are clubs, and thus:

[tex]p = \frac{13}{52} = 0.25[/tex]

0.25 = 25% probability of drawing a club in a standard deck of 52 cards.

For more about probabilities, you can check https://brainly.com/question/24104122

A study is conducted to compare the lengths of time required by men and women to assemble a certain product. Past experience indicates that the distribution of times for both men and women is approximately normal but the variance of the times for women is less than that for men. A random sample of times for 11 men and 14 women produced the following data:

Men:

n1= 11
s1= 6.1

Women:

n2= 14
s2= 5.3

Test the hypothesis that the variance for men is greater than for women. Use both p-value method and critical value approach.

Answers

Answer:

1.33 < 2.67 ; Fail to reject H0 at 0.05

Step-by-step explanation:

Given the data :

Men:

n1= 11

s1= 6.1

Women:

n2= 14

s2= 5.3

The hypothesis :

H0 : σ1² = σ2²

H1 : σ1² > σ2²

To calculate the test statistic ; we use th Ftest statistics ;

F statistic = Larger sample variance / Smaller sample variance

Fstatistic = s1² / s2² = 6.1² / 5.3² = 37.21/28.09 = 1.325

The F critical value at :

df numerator = n - 1 = 11 - 1 = 10

df denominator = n - 1 = 14 - 1 = 13

Using the F distribution table :

F critical = 2.671

Since

F statistic < F critical ; Fail to reject H0 at 0.05

We fail to reject the null hypothesis at significance level of H0 : s1² = s2²

For the men, we have:

n1= 11 s1= 6.1

For the women, we have:

n2= 14 s2= 5.3

The null and the alternate hypotheses are:

Null hypothesis H0 : s1² = s2²Alternate hypothesis H1 : s1² > s2²

The numerator and the denominator degrees of freedom are calculated as:

[tex]\mathbf{df = n -1}[/tex]

So, we have:

[tex]\mathbf{df_1 = 11 -1}[/tex]

[tex]\mathbf{df_1 = 10}[/tex] ----- numerator

[tex]\mathbf{df_2 = 14 -1}[/tex]

[tex]\mathbf{df_2 = 13}[/tex] ----- denominator

The test statistic of the f test is:

[tex]\mathbf{t = \frac{s_1^2}{s_2^2}}[/tex]

So, we have:

[tex]\mathbf{t = \frac{6.1^2}{5.3^2}}[/tex]

[tex]\mathbf{t = \frac{37.21}{28.09}}[/tex]

[tex]\mathbf{t = 1.325}[/tex]

The critical values at [tex]\mathbf{t = 1.325}[/tex] and the degrees of freedom is:

[tex]\mathbf{F= 2.671}[/tex]

By comparison, 1.325 is less than 2.671.

Hence, we fail to reject the null hypothesis at H0 : s1² = s2²

Read more about hypothesis at:

https://brainly.com/question/23639322

tìm tích phân tổng quát
xy'lny/x=x+ylny/x

Answers

Answer:

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Step-by-step explanation:

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The scatterplot shows the number of bedrooms in a house and the selling price for that house.



Calculate the residual for the house with 6 bedrooms, to the nearest thousand.

The residual for the house with 6 bedrooms is ___
-30k
-26k
26k
30k

Answers

Answer:

-26k, -26,000 ; (B)

ED2021

The residual for the house with 6 bedrooms is -26k.

What is Scatterplots?

Scatterplots are the plotting of set of points on a vertical axis and an horizontal axis. The shows the correlation extent between the numbers of the observed quantities.

Given is a scatterplot showing the selling price of houses with the number of bedrooms.

Equation of the line of best fit is given as,

y = 6.3x + 4.8

Residual = Actual value - Predicted value

From the scatterplot,

Actual selling price of house with 6 bedrooms = 40 × 10,000 = 400,000

Predicted selling price for 6 bedrooms = (6.3 × 6) + 4.8

                                                                 = 42.6 × 10,000

                                                                 = 426,000

Residual = 400,000 - 426,000

              = -26,000

Hence the residual is -26k.

Learn more about Residuals and Scatterplots here :

https://brainly.com/question/27847907

#SPJ2

Two sides of a triangle have lengths 13 m and 19 m. The angle between them is increasing at a rate of 2°/min. How fast is the length of the third side increasing when the angle between the sides of fixed length is 60°? (Round your answer to three decimal places.)

Answers

Answer:

The third side is increasing at an approximate rate of about 0.444 meters per minute.

Step-by-step explanation:

We are given a triangle with two sides having constant lengths of 13 m and 19 m. The angle between them is increasing at a rate of 2° per minute and we want to find the rate at which the third side of the triangle is increasing when the angle is 60°.

Let the angle between the two given sides be θ and let the third side be c.

Essentially, given dθ/dt = 2°/min and θ = 60°, we want to find dc/dt.

First, convert the degrees into radians:

[tex]\displaystyle 2^\circ \cdot \frac{\pi \text{ rad}}{180^\circ} = \frac{\pi}{90}\text{ rad}[/tex]

Hence, dθ/dt = π/90.

From the Law of Cosines:

[tex]\displaystyle c^2 = a^2 + b^2 - 2ab\cos \theta[/tex]

Since a = 13 and b = 19:

[tex]\displaystyle c^2 = (13)^2 + (19)^2 - 2(13)(19)\cos \theta[/tex]

Simplify:

[tex]\displaystyle c^2 = 530 - 494\cos \theta[/tex]

Take the derivative of both sides with respect to t:

[tex]\displaystyle \frac{d}{dt}\left[c^2\right] = \frac{d}{dt}\left[ 530 - 494\cos \theta\right][/tex]

Implicitly differentiate:

[tex]\displaystyle 2c\frac{dc}{dt} = 494\sin\theta \frac{d\theta}{dt}[/tex]

We want to find dc/dt given that dθ/dt = π/90 and when θ = 60° or π/3. First, find c:

[tex]\displaystyle \begin{aligned} c &= \sqrt{530 - 494\cos \theta}\\ \\ &=\sqrt{530 -494\cos \frac{\pi}{3} \\ \\ &= \sqrt{530 - 494\left(\frac{1}{2}\right)} \\ \\&= \sqrt{283\end{aligned}[/tex]

Substitute:

[tex]\displaystyle 2\left(\sqrt{283}\right) \frac{dc}{dt} = 494\sin\left(\frac{\pi}{3}\right)\left(\frac{\pi}{90}\right)[/tex]

Solve for dc/dt:

[tex]\displaystyle \frac{dc}{dt} = \frac{494\sin \dfrac{\pi}{3} \cdot \dfrac{\pi}{90}}{2\sqrt{283}}[/tex]

Evaluate. Hence:

[tex]\displaystyle \begin{aligned} \frac{dc}{dt} &= \frac{494\left(\dfrac{\sqrt{3}}{2} \right)\cdot \dfrac{\pi}{90}}{2\sqrt{283}}\\ \\ &= \frac{\dfrac{247\sqrt{3}\pi}{90}}{2\sqrt{283}}\\ \\ &= \frac{247\sqrt{3}\pi}{180\sqrt{283}} \\ \\ &\approx 0.444\text{ m/min}\end{aligned}[/tex]

The third side is increasing at an approximate rate of about 0.444 meters per minute.

9514 1404 393

Answer:

  0.444 m/min

Step-by-step explanation:

I find this kind of question to be answered easily by a graphing calculator.

The length of the third side can be found using the law of cosines. If the angle of interest is C, the two given sides 'a' and 'b', then the third side is ...

  c = √(a² +b² -2ab·cos(C))

Since C is a function of time, its value in degrees can be written ...

  C = 60° +2t° . . . . . where t is in minutes, and t=0 is the time of interest

Using a=13, and b=19, the length of the third side is ...

  c(t) = √(13² +19² -2·13·19·cos(60° +2t°))

Most graphing calculators are able to compute a numerical value of the derivative of a function. Here, we use the Desmos calculator for that. (Angles are set to degrees.) It tells us the rate of change of side 'c' is ...

  0.443855627418 m/min ≈ 0.444 m/min

_____

Additional comment

At that time, the length of the third side is about 16.823 m.

__

c(t) reduces to √(530 -494cos(π/90·t +π/3))

Then the derivative is ...

  [tex]c'(t)=\dfrac{494\sin{\left(\dfrac{\pi}{90}t+\dfrac{\pi}{3}\right)}\cdot\dfrac{\pi}{90}}{2\sqrt{530-494\cos{\left(\dfrac{\pi}{90}t+\dfrac{\pi}{3}}}\right)}}}\\\\c'(0)=\dfrac{247\pi\sqrt{3}}{180\sqrt{283}}\approx0.443855...\ \text{m/min}[/tex]

Use the slope-intercept form of the linear equation to write an equation of the line with given slope and y-intercept.
Slope: -6/5 y intercept (0,8)

Answers

Answer:

5y + 6x = 40

Step-by-step explanation:

hope it is well understood?

Slope intercept- y=mx+b
m is the slope
b is the y intercept (0,y)

y=-6/5x+8

Kayla made two paper chains. The paper links on one represented the number of days until her birthday, and the other showed the days until summer vacation. Altogether, she made 135 links for her chains. The birthday chain had twice as many links as the vacation chain. How many links are on Kayla's birthday chain?

Answers

Answer:

90 days

Step-by-step explanation:

b= number of days til  her birthday

s = number of days til summer

b+s =135

b = 2s

2s+s = 135

3s = 135

Divide by 3

3s/3 =135/3

s =45

b = 2s = 2(45) = 90

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