Ria is performing an experiment in chemistry class with a certain

It is believed that as many as 23% of adults over 50 never graduated from high school. We wish to see if this percentage is the

JulijaS [17]

Answer:

1) n=48

2) n=298

3) n=426

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

$p$ represent the real population proportion of interest

$\hat p$ represent the estimated proportion for the sample

n is the sample size required (variable of interest)

$z$ represent the critical value for the margin of error

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

Part 1

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.90=0.10$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=-1.64, z_{1-\alpha/2}=1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.1$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

We can assume that the estimated proportion is 0.23 for the 25 to 30 group. And replacing into equation (b) the values from part a we got:

$n=\frac{0.23(1-0.23)}{(\frac{0.1}{1.64})^2}=47.63$

And rounded up we have that n=48

Part 2

The margin of error on this case changes to 0.04 so if we use the same formula but changing the value for ME we got:

$n=\frac{0.23(1-0.23)}{(\frac{0.04}{1.64})^2}=297.7$

And rounded up we have that n=298

Part 3

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.04$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

We can assume that the estimated proportion is 0.23 for the 25 to 30 group. And replacing into equation (b) the values from part a we got:

$n=\frac{0.23(1-0.23)}{(\frac{0.04}{1.96})^2}=425.22$

And rounded up we have that n=426

3 0

2 years ago

The student senate at a local university is about to hold elections. A representative from the women’s sports program and a repr

Amanda [17]

Answer: H0: p1 ≤ p2, Ha: p1 > p2

Step-by-step explanation:

According to the information obtained, we can say that the hypothesis that determines that the percentages of support votes are different between the two incumbent candidates is as follows

H0: p1 ≤ p2, Ha: p1> p2

where the null hypothesis represents the difference between proportions

6 0

2 years ago

Mia has a conical container filled with chocolates. She knows that the volume of the container is equal to one-third of the prod

34kurt

For this case what you should do is create the equation based on:
"She knows that the volume of the container is equal to one-third of the product, the square of the radius of the base of the container, and the height of the container"
We have then that the Volume is given by:
V = (1/3) * (r ^ 2) * (h)
where,
r: radius of the base.
h: height of the container.
answer
The volume of the container is calculated with the following equation:
V = (1/3) * (r ^ 2) * (h)

7 0

2 years ago

Read 2 more answers

If n(A-B)=18,n(AuB)=70 and n(AnB)=25 then find n(B)

svp [43]

n(A-B) denotes elements which are in A but not in B

n(Au B) denotes elements in A and B

n(AnB) denotes elements that are common in A and B

Now I will add one more set

n(B-A) which denotes elements in B but not in A

So, n(AuB) = n(A-B) + n( B-A) +n(AnB)

70 = 18 +n(B-A) + 25