The sample size needed to estimate the difference between two population proportions to within a margin of error E with a significance level of ? can be found as follows. In the expression
E=z?p1(1?p1)n1+p2(1?p2)n2?????????????????????????
we replace both n1 and n2 by n (assuming that both samples have the same size) and replace each of p1, and p2, by 0.5 (because their values are not known). Then we solve for n, and get
n=(z?)22E2.
Finally, increase the value of n to the next larger integer number.
Use the above formula and Table C to find the size of each sample needed to estimate the difference between the proportions of boys and girls under 10 years old who are afraid of spiders. Assume that we want a 99% confidence level and that the error is smaller than 0.07.
n=______.

9514 1404 393

Answer:

  7.92 years

Step-by-step explanation:

We want to find t such that ...

  3 = 2^(t/5)

where 2^(t/5) is the annual multiplier when doubling time is 5 years.

Taking logs, we have ...

  log(3) = (t/5)log(2)

  t = 5·log(3)/log(2) ≈ 7.92 . . . years

It will take about 7.92 years for the population to triple.

Part a)

Time:distance

1:3

Part b)

6 hours

Part C)

81km

Answered by Gauthmath must click thanks and mark brainliest

Answer:

D

Step-by-step explanation:

The answer is D.

260 pairs

Step-by-step explanation:

220-100= 120

(29200+2000)÷120= 260

Answer:

Kindly check explanation

Step-by-step explanation:

H0 : μ = 15.7

H1 : μ < 15.7

This is a one sample t test :

Test statistic = (xbar - μ) ÷ (s/√(n))

n = sample size = 33

Using calculator :

The sample mean, xbar = 15.41

The sample standard deviation, s = 0.419

Test statistic = (15.41 - 15.70) ÷ (0.419/√(33))

Test statistic = - 3.976

Using the Pvalue calculator :

Degree of freedom, df = n - 1 ; 33 - 1 = 32

Pvalue(-3.976, 32) = 0.000187

Decison region :

Reject H0 if Pvalue < α

Since Pvalue < α ; we reject H0

There is significant evidence to conclude that the true average height of the seedlings treated with an extract from Vinca minor roots is less than 15.7 cm.

Volume = πr²h

Radius = 3yd

Height = 12yd

Take π = 22/7

Volume = 22/7×3×3×12

= 2376/7

= 339.4285714yd³

Rounding off to nearest tenth

= 339.43yd³

Answered by Gauthmath must click thanks and mark brainliest

Answer:

13.5

Step-by-step explanation:

Average rate of change=(f(2)-f(1))/1=-18/2^2-(-18))=13.5

9514 1404 393

Answer:

  undefined

Step-by-step explanation:

A rational expression is undefined when its denominator is zero.

Answer:

8.5

Step-by-step explanation:

Answer:

5/2

Step-by-step explanation:

Since MR=MR and XM=MY and angle XMR = angle RMY,

then triangle XMR is congruent to triangle RMY by SAS postulate

Therefore, XR has to be equal to RY.

Making 6x+2=17

subtracting both sides by 2 gives you 6x=15

then dividing both sides by 6 gives you x=15/6

simplifying this fraction gives you x=5/2

Hope this helps.

Answer:

Step-by-step explanation:

CD/6.5 = 2.6/4.9    This is the result of the angle bisector theorem.

The theorem basically says that the side opposite the angle being bisected is divided  the ratio of the sides enclosing the angle.

Multiply both sides of the proportion by 6.5

CD = 2.6 * 6.5 / 4.9

CD = 3.4489

CD = 3.4 rounded.

Answer:

C

Step-by-step explanation:

Given

[tex]\frac{x}{3}[/tex] < 5 ( multiply both sides by 3 to clear the fraction )

x < 15 → C

Answer:

Step-by-step explanation:

The relationship is linear, so the plant grows the same amount each day.

The height on the 2nd day was 8 inches:

h₂ = 8

The height on the 7th day was 20.5 inches:

h₇ = h₂ + (7-2)d = 8 + 5d = 20.5

d = 2.5

The plant grows 2.5 inches each day.

Answer:

[tex] \frac{x}{5} [/tex]

Step-by-step explanation:

[tex]f {}^{ - 1} (x)[/tex]

means inverse.

Find the inverse of the function.

[tex]f(x) = 5x[/tex]

Replace y with and vice versa.

[tex]x = {5y}[/tex]

Solve for y

[tex] \frac{x}{5} = y[/tex]

The inverse function is

[tex] \frac{x}{5} [/tex]

Answer:

The distance between two points (x₁, y₁) and (x₂, y₂) is given by:

[tex]d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}[/tex]

Now we know that point D, which we can write as (x, y), is at a distance of 8 units from the origin.

Where the origin is written as (0, 0)

We also know that point D is 6 units away along the y-axis.

Then point D could be:

(x, 6)

or

(x, -6)

Now, let's find the x-value for each case, we need to solve:

[tex]8 = \sqrt{(x - 0)^2 + (\pm6 - 0)^2}[/tex]

notice that because we have an even power, we will get the same value of x, regardless of which y value we choose.

[tex]8 = \sqrt{x^2 + 36} \\\\8^2 = x^2 + 36\\64 - 36 = x^2\\28 = x^2\\\pm\sqrt{28} = x\\\pm 5.29 = x[/tex]

So we have two possible values of x.

x = 5.29

and

x = -5.29

Then the points that are at a distance of 8 units from the origin, and that are 6 units away along the y-axis are:

(5.29, 6)

(5.29, -6)

(-5.29, 6)

(-5.29, -6)

Step-by-step explanation:

p-cheese wafers

q-chocolate wafers

p2 + q1 = $25

5(2) + 15(1) = $25

Just used numbers that added up to 20 starting from 2 going up

Answer:

[tex]\boxed {\boxed {\sf x \approx 1.9}}[/tex]

Step-by-step explanation:

We are asked to find x, a missing side in a triangle.

This is a right triangle because there is a small square in the corner representing a 90 degree or right angle. Therefore, we can use right triangle trigonometry. The three main functions are:

Examine the triangle. We will use angle S, measuring 54 degrees, for theta. Side QR, measuring x, is opposite angle S. Side QS, measuring 2.3, is the hypotenuse because it is opposite the right angle. Since we have the opposite and hypotenuse, we will use sine.

[tex]sin \theta = \frac {opposite}{hypotenuse}[/tex]

[tex]sin (54)= \frac{ x}{2.3}[/tex]

We are solving for x, so we must isolate the variable. It is being divided by 2.3 The inverse operation of division is multiplication, so we multiply both sides by 2.3

[tex]2.3* sin (54)= \frac{x}{2.3}*2.3[/tex]

[tex]2.3* sin (54)=x[/tex]

[tex]2.3*0.8090169944=x[/tex]

[tex]1.860739087 =x[/tex]

Round to the nearest tenth. The 6 in the hundredth place to the right tells us to round the 8 up to a 9.

[tex]1.9 \approx x[/tex]

x is approximately 1.9

Answer:

177.3 feet

This is a classic find the vertex of a parabola question.

if this was a calculus class the solution would be to take the derivative and set it equal to zero... -32t+ 105 = 0

BUT i assume that you are not in a calculus class..

so we try plan "B" the  highest (or lowest) point of parabola is it's vertex

the vertex formula is [-b/2a,f(-b/2a)]

in your problem a = -16, b=105, c= 5

so the "X" (TIME) is located at -(105)/(2*-16) = 3.28

plug in 3.28 into -16(3.28)^2 + 105(3.28) + 5 = 177.27

and you will get

Step-by-step explanation:

Answer:

The zeros of this function would be: x = 4 and x = 6, assuming that option got caught off while you were taking a picture.

Step-by-step explanation:

When they're asking for the zeros of this type of function, where is forms this kind of U-shape or also known as a quadratic equation, they're asking what the x-value is when y = 0, or when the line of the function touches the x-axis. Notice that it happens when x = 4 and when x = 6.

In short, it's asking what the x-value is of the points of the function when it intersects the x-axis. Hopefully my explanation wasn't too confusing. Good luck on the rest of the quiz!

[tex]\large{\underline {\underline {\pmb {\sf {\pink{Answer:}}}}}}[/tex]

Answer:

The largest whole number is the approximate of positive infinity ( to the nearest ones digit )

Answer:

the question is incomplete :-')

Answer:

$21.9 per gram

Step-by-step explanation:

Take the total price and divide by the number of grams

$162.18/7.4 grams

$21.91621 per gram

Rounding to the nearest tenth

$21.9 per gram

Answer:

$21.90 per gram (to the nearest tenth)

Step-by-step explanation:

Given information:

To find how much the necklace was worth per gram, divide the total cost by the number of grams:

[tex]\sf Worth\:per\:gram = \dfrac{\$162.18}{7.4\:g}=\$21.91621622... \:per\:gram[/tex]

Therefore, the necklace is worth $21.90 per gram (to the nearest tenth).

Step-by-step explanation:

hope it will help u

hope it will help u please mark me as brillient...

Answer:

939 is the answer

Step-by-step explanation:

plz Mark me as the brainlist

Answer:

The expected number of items that will be classified into group 1 is 100.

Step-by-step explanation:

For each observation, there are only two possible outcomes. Either it will be classified into group 1, or it will not. The probability of an observation being classified into group 1 is independent of any other observation, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

Probability of exactly x successes on n repeated trials, with p probability.

The expected value of the binomial distribution is:

[tex]E(X) = np[/tex]

400 observations

This means that [tex]n = 400[/tex]

Four mutually exclusive groups. The probability of a randomly selected item being classified into any of the four groups is equal.

This means that [tex]p = 0.25[/tex]

Then the expected number of items that will be classified into group 1 is

[tex]E(X) = np = 400*0.25 = 100[/tex]

100 is the answer.

Answer:

Hi!

Step-by-step explanation:

1234567890987654211234567890......

Step-by-step explanation:

12345678890098764321

Answer:

The minimum number of subjects needed is 385.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

The margin of error is:

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

95% confidence level

So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].

95% confidence, within 5 percentage points, and a previous estimate is not known.

The sample size is n for which M = 0.05. We don't know the true proportion, so we use [tex]\pi = 0.5[/tex]

Then

[tex]M = z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

[tex]0.05 = 1.96\sqrt{\frac{0.5*0.5}{n}}[/tex]

[tex]0.05\sqrt{n} = 1.96*0.5[/tex]

[tex]\sqrt{n} = \frac{1.96*0.5}{0.05}[/tex]

[tex](\sqrt{n})^2 = (\frac{1.96*0.5}{0.05})^2[/tex]

[tex]n = 384.16[/tex]

Rounding up:

The minimum number of subjects needed is 385.

Answer:

máy ...

xác suất để một máy tính bảng có hệ điều hành B sử dụng ổn định trong 2 năm đầu tiên. Add answer

Answer:

t- shirt cost £7, hat cost £3

Step-by-step explanation:

let t represent cost of t- shirt and h represent cost of hat , then

4t + h = 31  → (1)

2t + h = 17 → (2)

Subtract (2) from (1) term by term to eliminate h

(4t - 2t) + (h - h) = 31 - 17 , that is

2t = 14 ( divide both sides by 2 )

t = 7

Substitute t = 7 into either of the 2 equations and solve for h

Substituting into (1)

4(7) + h = 31

28 + h = 31 ( subtract 28 from both sides )

h = 3

t- shirt cost £7 and hat cost £3

Answer:

c

Step-by-step explanation:

took the test so i assume its this question

Answer:

For any rectangle, the one with the largest area will be the one whose dimensions are as close to a square as possible.

However, the dividers change the process to find this maximum somewhat.

Letting x represent two sides of the rectangle and the 3 parallel dividers, we have 2x+3x = 5x.

Letting y represent the other two sides of the rectangle, we have 2y.

We know that 2y + 5x = 750.

Solving for y, we first subtract 5x from each side:

2y + 5x - 5x = 750 - 5x

2y = - 5x + 750

Next we divide both sides by 2:

2y/2 = - 5x/2 + 750/2

y = - 2.5x + 375

We know that the area of a rectangle is given by

A = lw, where l is the length and w is the width. In this rectangle, one dimension is x and the other is y, making the area

A = xy

Substituting the expression for y we just found above, we have

A = x (-2.5x+375)

A = - 2.5x² + 375x

This is a quadratic equation, with values a = - 2.5, b = 375 and c = 0.

To find the maximum, we will find the vertex. First we find the axis of symmetry, using the equation

x = - b/2a

x = - 375/2 (-2.5) = - 375/-5 = 75

Substituting this back in place of every x in our area equation, we have

A = - 2.5x² + 375x

A = - 2.5 (75) ² + 375 (75) = - 2.5 (5625) + 28125 = - 14062.5 + 28125 = 14062.5

Step-by-step explanation: