Answer:
The critical value is [tex]T_c = 1.7056[/tex]
The 90% confidence interval for the mean repair cost for the refrigerators is ($52.875, $68.165).
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 27 - 1 = 26
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 26 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.9}{2} = 0.95[/tex]. So we have T = 1.7056, which means that the critical value is [tex]T_c = 1.7056[/tex]
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 1.7056\frac{23.29}{\sqrt{27}} = 7.645[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 60.52 - 7.645 = $52.875.
The upper end of the interval is the sample mean added to M. So it is 60.52 + 7.645 = $68.165.
The 90% confidence interval for the mean repair cost for the refrigerators is ($52.875, $68.165).
A record store owner finds that 20% of customers entering her store make a purchase. One morning 180 people, who can be regarded as a random sample of all customers, enter the store.
a. What is the mean of the distribution of the sample proportion of customers making a purchase?
b) What is the variance of the sample proportion?
c) What is the standard error of the sample proportion?
d) What is the probability that the sample proportion is less than 0.15?
Answer:
a) 0.2
b) 0.0009
c) 0.0298
d) 0.0465 = 4.65% probability that the sample proportion is less than 0.15.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
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.
Central Limit Theorem
The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean [tex]\mu = p[/tex] and standard deviation [tex]s = \sqrt{\frac{p(1-p)}{n}}[/tex]
20% of customers entering her store make a purchase.
This means that [tex]p = 0.2[/tex]
180 people
This means that [tex]n = 180[/tex]
a. What is the mean of the distribution of the sample proportion of customers making a purchase?
By the Central Limit Theorem, [tex]\mu = p = 0.2[/tex].
b) What is the variance of the sample proportion?
The standard deviation is:
[tex]s = \sqrt{\frac{0.2*0.8}{180}} = 0.0298[/tex]
Variance is the square of the standard deviation, so:
[tex]s^2 = (0.0298)^2 = 0.0009[/tex]
c) What is the standard error of the sample proportion?
As found in the previous item, 0.0298.
d) What is the probability that the sample proportion is less than 0.15?
This is the p-value of Z when X = 0.15. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{0.15 - 0.20}{0.0298}[/tex]
[tex]Z = -1.68[/tex]
[tex]Z = -1.68[/tex] has a p-value of 0.0465.
0.0465 = 4.65% probability that the sample proportion is less than 0.15.
The tires Mary wants to buy for her car cost $100 per tire. A store is offering the following deal. Buy a tire and get the 4th tire for 75% off! Mary will buy 4 tires using the deal. A sales tax of 8% will be charged after applying the discount. How much money will Mary saveby using the deal instead of paying the full price for all 4 tires?
she saved $162
hope it helps
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).
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.
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:
Learn more about poisson distribution here:
https://brainly.com/question/7879375
Solve the equation Axb by using the LU factorization given for A. Also solve Axb by ordinary row reduction. A , b Let Lyb and Uxy. Solve for x and y. nothing nothing Row reduce the augmented matrix and use it to find x. The reduced echelon form of is nothing, yielding x nothing.
Answer: Hello your question is poorly written attached below is the complete question
answer:
[tex]y = \left[\begin{array}{ccc}-4\\-11\\5\end{array}\right][/tex]
[tex]x = \left[\begin{array}{ccc}16\\12\\-40\end{array}\right][/tex]
Step-by-step explanation:
[tex]y = \left[\begin{array}{ccc}-4\\-11\\5\end{array}\right][/tex]
[tex]x = \left[\begin{array}{ccc}16\\12\\-40\end{array}\right][/tex]
attached below is the detailed solution using LU factorization
__ (5 + 4) = 2 * 5 + 2 * 4
PLEASE EXPLAIN HOW YOU GOT THE ANSWER
Answer:
x = 2
Step-by-step explanation:
→ Simplify
x × ( 9 ) = 10 + 8
→ Further simplify
9x = 18
→ Divide both sides by 9
x = 2
In each figure below, find m<1 and m<2 if a is parallel to b. You don't have to show work.
please help i need this by tonight will give brainliest
Answer:
m <5 = 71 degrees.
m <8 = 109 degrees.
The following are on a parabola defining the edge of a ski
(-4, 1), (-2, 0.94), (0.1)
The general form for the equation of a parabola is:
Ax^2+ Bx +C= y
Required:
a. Use the x- and y-values of 1 of the points to build a linear equation with 3 variables: A, B, and C.
b. Repeat this process with 1 of the other to build a 2nd linear equation.
c. Record your equation here. Repeat this process with the other point to build a 3rd equation.
9514 1404 393
Answer:
a) 16A -4B +C = 1
b) 4A -2B +C = 0.94
c) C = 1
Step-by-step explanation:
Substitute the x- and y-values into the general form equation.
a. A(-4)² +B(-4) +C = 1
16A -4B +C = 1
__
b. A(-2)² +B(-2) +C = 0.94
4A -2B +C = 0.94
__
c. A(0)² +B(0) +C = 1
C = 1
_____
Additional comment
Solving these equations gives A=0.015, B=0.06, C=1. The quadratic is ...
0.015x² +0.06x +1 = y
Choose the correct answer.
The History Activities were about ___ and ___. They were both from ___. One of them had a ___ named after him. The other had a ___ named after him. The work they did together on a problem they got from a ___ laid the foundation for probability theory.
A. Pascal, Decartes, England, graph, book, relative
B. Luniz, Kolmogrov, Germany, church, square, teacher
C. Fermat, Luniz, England, law, diagram, priest
D. Pascal, Fermat, France, triangle, theorem, gambler
Answer:
I say Its letter d
Step-by-step explanation:
I hope this help
Plz help
Need answers ASAP
Answer:
1. cube
2. square pyramid
4. cone
5. cube
Emily, Yani and Joyce have a total of 3209 stickers. Yani has 2 times
as many stickers as Joyce. Emily has 279 more stickers than Yani. How
many more stickers does Emily have than Joyce?
Answer:
279+x
Step-by-step explanation:
Emily + Yani + Joyce=3209 stickers
if Yani has 2 times as many stickers as Joyce:this statement states that Joyce has x stickers and Yani has 2x stickers because x multiplied by 2"Emily has 279 more stickers than Yani":therefore the equation for Emily will be ;279+2xhow many stickers does Emily have than Joyce:
(279+2x)-(x)
279+2x-x
=279+x
A company wants to decrease their energy use by 17%. If their electric bill is currently $2500 a month, what will their bill be if they are successful
Suppose that a customer is purchasing a car. He conducts an experiment in which he puts 10 gallons of gas in the car and drives it until it runs out of gas. He conducts this experiment 15 times on each car and records the number of miles driven.
Car 1 Car 2
214 220
245 221
239 244
224 225
220 258
295 259
Describe each data set, that is determine the shape, center, and spread
i. Sample mean for Car 1
ii. Sample mean for Car 2
Answer:
Kindly check explanation
Step-by-step explanation:
Given the data :
Car 1 Car 2
214 220
245 221
239 244
224 225
220 258
295 259
Ordered data:
Car 1 : 214, 220, 224, 239, 245, 295
Sample mean = ΣX/ n ; n = sample size = 6
Sample mean = 1437 / 6 = 239.5
Median = 1/2(n+1)th term = 1/2(7) = 3.5th term
Median = (3rd + 4th) /2 = (224 + 239) /2 = 231.5
Sample standard deviation; √(Σ(x - xbar)²/n-1 ) = 29.60 (using calculator)
Car 2 : 220, 221, 225, 244, 258, 259
Sample mean = ΣX/ n ; n = sample size = 6
Sample mean = 1427 / 6 = 237.833
Median = 1/2(n+1)th term = 1/2(7) = 3.5th term
Median = (3rd + 4th) /2 = (225 + 244) /2 = 234.5
Sample standard deviation; √(Σ(x - xbar)²/n-1 ) = 18.21 (using calculator)
Suppose v1 , v2 , v3 ,v4 are vectors in R3.
(a) These four vectors are dependent because_________ .
(b) The two vectors v1 and v2 will bedependent if_________ .
(c) The vectors v1 and (0, 0, 0) are dependent because________ .
Answer:
a. These four vectors are dependent because there are columns of 3 by 4 matrix with one free variable.
b. If one is a multiple of other
c. c1v1 + c20 = 0 has nontrivial solution.
Step-by-step explanation:
Any set of 4 or more vectors must be linearly dependent. The non trivial combination of vector may produce zero as the set is linearly dependent. The vector v1 and v2 will be dependent if one is the multiple of the other.
At basketball practice, you made 59 out of 80 shots.
Which choice is closest to the percentage of shots you mad
Answer:
73.5 Percent ...........
Answer:
The closest percentage of shots you made is 75%. Please mark brainliest.
I believe the choices are:
60%
70%
75%
80%
Therefore the answer 75%
Step-by-step explanation:
59/80 = 0.7375
Rounded up is 0.75
0.75 x 100 = 75%
Hope this helps.
Have a nice day amazing person there.
MAY GOD RICHLY BLESS YOU!!
identify the constant term in the given expression : -3xy + 10
plz
Step-by-step explanation:
well, what does the word "constant" tell you ?
e.g. "this is a constant reminder of ..."
a constant is steady and unchanging. always the same.
so, what could be the constant part/term in the expression ?
-3xy ? is that always the same value ? no matter what values you assign to x, y (and whatever other variables there might be in the system)?
or
10 ? is that always the same value, no matter what values are assigned to x, y, ... ?
there are no other parts/terms I can see here.
so, please use your common sense and pick the right one. you can do that !
this is so simple. to outright write the answer to this feels like an offense. also against your own intelligence.
write your answer in simplest radical form
Answer:
c = 4√2
Step-by-step explanation:
From the question given above, the following data were obtained:
Angle θ = 30
Opposite = 2√2
Hypothenus = c =?
We can obtain the value of c by using the sine ratio as illustrated below:
Sine θ = Opposite / Hypothenus
Sine 30 = 2√2 / c
½ = 2√2 / c
Cross multiply
c = 2 × 2√2
c = 4√2
Therefore, the value of c is 4√2.
five brothers of 4, 9, 11, 13 and 16 years respectively, receive an inheritance of 1,500,000, the will stipulated that that amount must be shared by the heirs so that, placed the shares in a bank, they would result in equal capitalized amounts, when each one reached 21, could raise his share. Knowing that the bank charges an interest rate of 9% per year, what is the amount of each share?
9514 1404 393
Answer:
Youngest to oldest:
160,406.86246,805.83293,230.01348,386.58451,170.72Step-by-step explanation:
At 9% interest per year, the present value of 1 at age 20 is ...
p(a) = 1.09^(a-20)
Adding the present values for the different ages, we get a total of about 2.35528984846. Dividing the inheritance by that amount gives the multiplier for each of the present value numbers. The result is the list of shares shown above. At age 20, each brother will inherit about 636,864.29.
__
Additional comment
This is the sort of question that suggests the use of a graphing calculator or spreadsheet for doing the tedious number crunching.
(We assume the bank pays 9% per year, rather than charges 9% per year.)
A company that produces DVD drives has a 12% defective rate. Let X represent the number of defectives in a random sample of 55 of their drives.
Required:
a. What is the probability the sample will contain exactly 8 defective drives?
b. What is the probability the sample will contain more than 8 defective drives?
c. What is the probability the sample will contain less than 8 defective drives?
d. What is the expected number of defective drives in the sample?
Answer:
a) 0.1287 = 12.87% probability the sample will contain exactly 8 defective drives
b) 0.2092 = 20.92% probability the sample will contain more than 8 defective drives.
c) 0.6621 = 66.21% probability the sample will contain less than 8 defective drives.
d) The expected number of defective drives in the sample is 6.6
Step-by-step explanation:
For each DVD, there are only two possible outcomes. Either it is defective, or it is not. The probability of a DVD being defective is independent of any other DVD, which means that the binomial probability distribution is used to solve this question.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
A company that produces DVD drives has a 12% defective rate.
This means that [tex]p = 0.12[/tex]
Let X represent the number of defectives in a random sample of 55 of their drives.
This means that [tex]n = 55[/tex]
a. What is the probability the sample will contain exactly 8 defective drives?
This is [tex]P(X = 8)[/tex]. So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 8) = C_{55,8}.(0.12)^{8}.(0.88)^{47} = 0.1287[/tex]
0.1287 = 12.87% probability the sample will contain exactly 8 defective drives.
b. What is the probability the sample will contain more than 8 defective drives?
This is:
[tex]P(X > 8) = 1 - P(X \leq 8)[/tex]
In which:
[tex]P(X \leq 8) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8)[/tex]
Then
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{55,0}.(0.12)^{0}.(0.88)^{55} = 0.0009[/tex]
[tex]P(X = 1) = C_{55,1}.(0.12)^{1}.(0.88)^{54} = 0.0066[/tex]
[tex]P(X = 2) = C_{55,2}.(0.12)^{2}.(0.88)^{53} = 0.0244[/tex]
[tex]P(X = 3) = C_{55,3}.(0.12)^{3}.(0.88)^{52} = 0.0588[/tex]
[tex]P(X = 4) = C_{55,4}.(0.12)^{4}.(0.88)^{51} = 0.1043[/tex]
[tex]P(X = 5) = C_{55,5}.(0.12)^{5}.(0.88)^{50} = 0.1450[/tex]
[tex]P(X = 6) = C_{55,8}.(0.12)^{6}.(0.88)^{49} = 0.1648[/tex]
[tex]P(X = 7) = C_{55,7}.(0.12)^{7}.(0.88)^{48} = 0.1573[/tex]
[tex]P(X = 8) = C_{55,8}.(0.12)^{8}.(0.88)^{47} = 0.1287[/tex]
So
[tex]P(X \leq 8) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) = 0.0009 + 0.0066 + 0.0244 + 0.0588 + 0.1043 + 0.1450 + 0.1648 + 0.1573 + 0.1287 = 0.7908[/tex]
[tex]P(X > 8) = 1 - P(X \leq 8) = 1 - 0.7908 = 0.2092[/tex]
0.2092 = 20.92% probability the sample will contain more than 8 defective drives.
c. What is the probability the sample will contain less than 8 defective drives?
This is:
[tex]P(X < 8) = 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]
With the values we found in b.
[tex]P(X < 8) = 0.0009 + 0.0066 + 0.0244 + 0.0588 + 0.1043 + 0.1450 + 0.1648 + 0.1573 = 0.6621[/tex]
0.6621 = 66.21% probability the sample will contain less than 8 defective drives.
d. What is the expected number of defective drives in the sample?
The expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
In this question:
[tex]E(X) = 55(0.12) = 6.6[/tex]
The expected number of defective drives in the sample is 6.6
Banking fees have received much attention during the recent economic recession as bankslook for ways to recover from the crisis. A sample of 31 customers paid an average fee of $11.53 permonth on their checking accounts. Assume the population standard deviation is $1.50. Calculatethe margin of error for a 90% confidence interval for the mean banking fee.
Answer:
The margin of error for a 90% confidence interval for the mean banking fee is of $0.44.
Step-by-step explanation:
We have that to find our [tex]\alpha[/tex] level, that is the subtraction of 1 by the confidence interval divided by 2. So:
[tex]\alpha = \frac{1 - 0.9}{2} = 0.05[/tex]
Now, we have to find z in the Z-table as such z has a p-value of [tex]1 - \alpha[/tex].
That is z with a pvalue of [tex]1 - 0.05 = 0.95[/tex], so Z = 1.645.
Now, find the margin of error M as such
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
In which [tex]\sigma[/tex] is the standard deviation of the population and n is the size of the sample.
Sample of 31:
This means that [tex]n = 31[/tex]
Assume the population standard deviation is $1.50.
This means that [tex]\sigma = 1.5[/tex]
Calculate the margin of error for a 90% confidence interval for the mean banking fee.
[tex]M = z\frac{\sigma}{\sqrt{n}}[/tex]
[tex]M = 1.645\frac{1.5}{\sqrt{31}}[/tex]
[tex]M = 0.44[/tex]
The margin of error for a 90% confidence interval for the mean banking fee is of $0.44.
Solve for x then measure to find A
Answer:
[tex]125 \: \: degrees[/tex]
Step-by-step explanation:
As the 2 lines are parallel
<A = <B ( Alternative Angles)
[tex]6x + 5 = 4x + 45 \\ 6x - 4x = 45 - 5 \\ 2x = 40 \\ x = 20[/tex]
[tex]<A = 6x + 5 \\ = 6 \times 20 + 5 \\ = 120 + 5 \\ = 125[/tex]
<A=6x+5
=6×20+5
=120+5
=125
<B=4x+45
=4×20+45
=80+45
=125
it is alternate angle they are equal each other
<A = < B
[tex]6x + 5 = 4x + 45 \\ 6x - 4x = 45 - 5 \\ 2x = 40 \\ x = \frac{40}{2} \\ x = 20 \\ \\ [/tex]
Which of the following pairs of functions are inverses of each other?
A. f(x) = 5 + x and g(x) = 5 - x
B. f(x) = 2x -9 and g(x)=x+9/2
C. f(x) = 3-6 and g(x)=x+6/2
D. f(x)= x/3+4 and g(x) = 3x - 4
The pair of functions that are inverses of each other is B. f(x) = 2x - 9 and g(x) = x + 9/2.
To determine if two functions are inverses of each other, we need to check if the composition of the functions results in the identity function, which is f(g(x)) = x and g(f(x)) = x.
Let's analyze the given options:
A. f(x) = 5 + x and g(x) = 5 - x
To check if they are inverses, we compute f(g(x)) = f(5 - x) = 5 + (5 - x) = 10 - x, which is not equal to x. Similarly, g(f(x)) = g(5 + x) = 5 - (5 + x) = -x, which is also not equal to x. Therefore, these functions are not inverses.
B. f(x) = 2x - 9 and g(x) = x + 9/2
By calculating f(g(x)) and g(f(x)), we find that f(g(x)) = x and g(f(x)) = x, which means these functions are inverses of each other.
C. f(x) = 3 - 6 and g(x) = x + 6/2
Similar to option A, we compute f(g(x)) and g(f(x)), and find that they are not equal to x. Hence, these functions are not inverses.
D. f(x) = x/3 + 4 and g(x) = 3x - 4
After evaluating f(g(x)) and g(f(x)), we see that f(g(x)) = x and g(f(x)) = x. Therefore, these functions are inverses of each other.
In summary, the pair of functions that are inverses of each other is B. f(x) = 2x - 9 and g(x) = x + 9/2.
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Given FE=23.5, find BD.
Answer:
11.75
Step-by-step explanation:
The required triangle is attached below :
The triangle AFE has it's by the mid segment as BD ;as B is the mid-point of line EA ; and D is the mid-point of line FA ;
HENCE, The Length of the midsegment BD = 1/2FE
Hence, BD =. 1/2 * 23.5
BD = 23.5 / 2 = 11.75
The automatic opening device of a military cargo parachute has been designed to open when the parachute is 185 m above the ground. Suppose opening altitude actually has a normal distribution with mean value 185 and standard deviation 32 m. Equipment damage will occur if the parachute opens at an altitude of less than 100 m. What is the probability that there is equipment damage to the payload of at least one of five independently dropped parachutes
Answer:
0.0193 = 1.93% probability that there is equipment damage to the payload of at least one of five independently dropped parachutes.
Step-by-step explanation:
For each parachute, there are only two possible outcomes. Either there is damage, or there is not. The probability of there being damage on a parachute is independent of any other parachute, which means that the binomial probability distribution is used to solve this question.
To find the probability of damage on a parachute, the normal distribution is used.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
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.
Probability of a parachute having damage.
The opening altitude actually has a normal distribution with mean value 185 and standard deviation 32 m, which means that [tex]\mu = 185, \sigma = 32[/tex]
Equipment damage will occur if the parachute opens at an altitude of less than 100 m, which means that the probability of damage is the p-value of Z when X = 100. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{100 - 185}{32}[/tex]
[tex]Z = -2.66[/tex]
[tex]Z = -2.66[/tex] has a p-value of 0.0039.
What is the probability that there is equipment damage to the payload of at least one of five independently dropped parachutes?
0.0039 probability of a parachute having damage, which means that [tex]p = 0.0039[/tex]
5 parachutes, which means that [tex]n = 5[/tex]
This probability is:
[tex]P(X \geq 1) = 1 - P(X = 0)[/tex]
In which
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 0) = C_{5,0}.(0.0039)^{0}.(0.9961)^{5} = 0.9807[/tex]
Then
[tex]P(X \geq 1) = 1 - P(X = 0) = 1 - 0.9807 = 0.0193[/tex]
0.0193 = 1.93% probability that there is equipment damage to the payload of at least one of five independently dropped parachutes.
Solve the following system of equations and show all your work y=2x^2 y=3x-1
Answer:
( 1/2 ; 1/2 ) and ( 1 ; 2 )
Step-by-step explanation:
y = 2x².............1
y = 3x-1............2
2x²=3x-1
2x²-3x+1 = 0
(2x-1)(x-1) = 0
x = 1/2 or x = 1
y = 1/2 or y = 2
I really Need help solving this problem!
Answer:
Hello,
Answer A : 11.2 ≤ X ≤ 29.2
Step-by-step explanation:
[tex]Z=\dfrac{X-20.2}{4.5} \\\\X=4.5*Z+20.2\\\\For\ Z=-2, \ X=4.5*(-2)+20.2=11.2\\For\ Z=2, \ X=4.5*2+20.2=29.2\\[/tex]
Identify the first 4 terms in the arithmetic sequence given by the explicit formula ƒ(n) = 8 + 3(n – 1).
Step-by-step explanation:
simple formula application :
a1 = 8 + 3×(1-1) = 8
a2 = 8 + 3×(2-1) = 11
a3 = 8 + 3×(3-1) = 14
a4 = 8 + 3×(4-1) = 17
...
Find the missing side of the triangle
Answer:
x = 7[tex]\sqrt{2}[/tex]
Step-by-step explanation:
Pytago:
[tex]7^2 + 7^2 = x^2\\x = \sqrt{7^2 + 7^2} \\x = 7\sqrt{2}[/tex]
Step-by-step explanation:
In a right triangle, you can find the leg of the triangle by using the Pythagorean theorem.
[tex]a^2+b^2=c^2[/tex]
In this case, we have [tex]7^2+7^2=c^2[/tex], or
[tex]c^2=98[/tex]
[tex]\sqrt{98}[/tex]≅[tex]9.9[/tex]
The volume of a gas with a pressure of 1.2 atm increases from 1.0 L to 4.0 L. What is the final pressure of the gas, assuming constant temperature?
(a) 1.2 atm
(b) 0.30 atm
(c) 3.3 atm
(d) 4.8 atm
(e) 1.0 atm
Answer:
(b) 0.30 atm
Step-by-step explanation:
Given data
Initial pressure= 1.2atm
Initial volume= 1.0L
Final volume= 4.0L
Final pressure= ???
Let us apply the gas formula to find the Final pressure
P1V1= P2V2
Substitute
1.2*1= x*4
Divide both sides by 4
1.2/4= x
x= 0.3atm
Hence the final pressure is 0.3 atm
Juan had 5 candy bars for himself and 4 friends to share with after lunch. Then three other friends joined them. Juan divided the 5 candy bars equally with all of his friends. How much did each person get?
Answer:
5/8
Step-by-step explanation:
There are 5 people when 3 more join for a total of 8 people
5 candy bars divided by 8 people
Take the candy bars and divide by the people
5/8
Evaluate the functions
Answer:
Step-by-step explanation:
