Question 1

In the equation for confidence intervals, $\bar{X} \pm z_{a}\left(\frac{s}{\sqrt{n}}\right)$ , $Z_{a}$ corresponds to ______.

Accepted Answer

A)   the alpha we are using (the level of confidence) 
B)   the standard deviation of our sample
C)   the variance of our sample
D)   the lower limit of our confidence interval  A

Question 2

______ are the lower and upper boundaries of the confidence interval.

Accepted Answer

A)   Point estimates
B)   Population estimates
C)   Confidence limits
D)   Confidence levels C

Question 3

The following equation, $\sigma_{p}=\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$ , is used to compute ______.

Accepted Answer

A)   standard error of a small sample
B)   standard error of the proportion
C)   variance of the proportion
D)   confidence limits of proportion  B

Question 4

Point estimates are the estimate of the mean and proportion that we obtained from a sample.

Accepted Answer

A) True 
 B)False

Question 5

As compared to a z-distribution, a t-distribution is ______.

Accepted Answer

A)   flatter
B)   more precise
C)   positively skewed
D)   negatively skewed

Question 6

As sample sizes ______, the sample means of the sampling distribution cluster more tightly around the population mean.

Accepted Answer

A)   increases
B)   decreases
C)   stays the same
D)   changes

Question 7

A confidence interval is equal to Confidenceinterval $ = $ pointestimate $ \pm $________$ ? $

Accepted Answer

A)   the variance
B)   mean deviation
C)   margin of error
D)   alpha

Question 8

For a sample of 30 individuals, we would rely on the ______.

Accepted Answer

A)   z-distribution
B)   square root of the variance
C)   t-distribution
D)   confidence limits

Question 9

For a sample of 29 individuals, we would rely on the ______.

Accepted Answer

A)   z-distribution
B)   central limit theorem
C)   t-distribution
D)   confidence limits

Question 10

Discuss the difference between the 95% and the 99% confidence intervals.

Accepted Answer

The answer of Discuss the difference between the 95% and...

Question 11

Which equation is used to find the degrees of freedom in a sample of 29 individuals?

Accepted Answer

A)    n−2n-2n−2 
B)    n−n-n−  -3
C)    n−1n-1n−1 
D)    n−nn-nn−n

Question 12

If a research reports "The margin of sampling error is $\pm$ 8 points at the 95% confidence level", this means that ______.

Accepted Answer

A)   they are 95% confident that their exact point estimate is correct
B)   they are 95% confident that the true population parameter is included in the intervals of  ±\pm±  8 points
C)   they are 95% confident that the true population parameter is included in the intervals of  ±\pm±  4 points
D)   they are 95% they are correct

Question 13

In the equation for the standard deviation of the sampling distribution, $\frac{s}{\sqrt{n}}$ , where s is the standard deviation and n is the sample size, how could one get more precise estimates that differ less from one another?

Accepted Answer

A)   increase s to expand the distribution
B)   increase the sample size (n)  because as the denominator increase the resulting value decreases
C)   decrease the sample size (n)  because as the denominator decreases the resulting value decreases
D)   collect data that are not skewed

Question 14

A confidence interval is ______.

Accepted Answer

A)   the lower and upper boundaries of the confidence interval
B)   a statistical interval around a point estimate (the mean)  that provides a specified level of confidences for the true population parameter
C)   a range of numbers that tells us the probability that our estimate is wrong
D)   range of values for a variable that has a stated probability of containing an unknown population mean

Question 15

On a single graph, draw a t-distribution. Then overlay the t-distribution with a z-distribution. How are they different? What implications do these differences have for sampling error, estimates, and confidence intervals?

Accepted Answer

The answer of On a single graph, draw a t-distribution....

Question 16

At what sample size are the t- and z-distributions identical?

Accepted Answer

A)   120
B)   100
C)   30
D)   50

Question 17

The 95% confidence interval will be wider than the 99% confidence interval.

Accepted Answer

A) True 
 B)False

Question 18

A z-score of 2.58 corresponds to what size alpha?

Accepted Answer

A)   .001
B)   .01
C)   .05
D)   .10

Question 19

A confidence level of 90% is what size alpha?

Accepted Answer

A)   .001
B)   .01
C)   .05
D)   .10

Question 20

When calculating the confidence interval for a small sample the t-distribution is utilized to obtain the critical value.

Accepted Answer

A) True 
 B)False

Exam 7: Point Estimation and Confidence Intervals

In the equation for confidence intervals, $\bar{X} \pm z_{a}\left(\frac{s}{\sqrt{n}}\right)$ , $Z_{a}$ corresponds to ______.

______ are the lower and upper boundaries of the confidence interval.

The following equation, $\sigma_{p}=\sqrt{\frac{\hat{p}(1-\hat{p}) }{n}}$ , is used to compute ______.

Point estimates are the estimate of the mean and proportion that we obtained from a sample.

As compared to a z-distribution, a t-distribution is ______.

As sample sizes ______, the sample means of the sampling distribution cluster more tightly around the population mean.

A confidence interval is equal to Confidenceinterval $=$ pointestimate $\pm$ ________ $?$

For a sample of 30 individuals, we would rely on the ______.

For a sample of 29 individuals, we would rely on the ______.

Discuss the difference between the 95% and the 99% confidence intervals.

Which equation is used to find the degrees of freedom in a sample of 29 individuals?

If a research reports "The margin of sampling error is $\pm$ 8 points at the 95% confidence level", this means that ______.

In the equation for the standard deviation of the sampling distribution, $\frac{s}{\sqrt{n}}$ , where s is the standard deviation and n is the sample size, how could one get more precise estimates that differ less from one another?

A confidence interval is ______.

On a single graph, draw a t-distribution. Then overlay the t-distribution with a z-distribution. How are they different? What implications do these differences have for sampling error, estimates, and confidence intervals?

At what sample size are the t- and z-distributions identical?

The 95% confidence interval will be wider than the 99% confidence interval.

A z-score of 2.58 corresponds to what size alpha?

A confidence level of 90% is what size alpha?

When calculating the confidence interval for a small sample the t-distribution is utilized to obtain the critical value.

Exam 7: Point Estimation and Confidence Intervals

In the equation for confidence intervals, Xˉ±za(sn) \bar{X} \pm z_{a}\left(\frac{s}{\sqrt{n}}\right) Xˉ±za​(n​s​) , ZaZ_{a}Za​ corresponds to ______.

______ are the lower and upper boundaries of the confidence interval.

The following equation, σp=p^(1−p^) n\sigma_{p}=\sqrt{\frac{\hat{p}(1-\hat{p}) }{n}}σp​=np^​(1−p^​) ​​ , is used to compute ______.

Point estimates are the estimate of the mean and proportion that we obtained from a sample.

As compared to a z-distribution, a t-distribution is ______.

As sample sizes ______, the sample means of the sampling distribution cluster more tightly around the population mean.

A confidence interval is equal to Confidenceinterval = = = pointestimate ± \pm ± ________ ? ? ?

For a sample of 30 individuals, we would rely on the ______.

For a sample of 29 individuals, we would rely on the ______.

Discuss the difference between the 95% and the 99% confidence intervals.

Which equation is used to find the degrees of freedom in a sample of 29 individuals?

If a research reports "The margin of sampling error is ±\pm± 8 points at the 95% confidence level", this means that ______.

In the equation for the standard deviation of the sampling distribution, sn\frac{s}{\sqrt{n}}n​s​ , where s is the standard deviation and n is the sample size, how could one get more precise estimates that differ less from one another?

A confidence interval is ______.

On a single graph, draw a t-distribution. Then overlay the t-distribution with a z-distribution. How are they different? What implications do these differences have for sampling error, estimates, and confidence intervals?

At what sample size are the t- and z-distributions identical?

The 95% confidence interval will be wider than the 99% confidence interval.

A z-score of 2.58 corresponds to what size alpha?

A confidence level of 90% is what size alpha?

When calculating the confidence interval for a small sample the t-distribution is utilized to obtain the critical value.

In the equation for confidence intervals, $\bar{X} \pm z_{a}\left(\frac{s}{\sqrt{n}}\right)$ , $Z_{a}$ corresponds to ______.

The following equation, $\sigma_{p}=\sqrt{\frac{\hat{p}(1-\hat{p}) }{n}}$ , is used to compute ______.

A confidence interval is equal to Confidenceinterval $=$ pointestimate $\pm$ ________ $?$

If a research reports "The margin of sampling error is $\pm$ 8 points at the 95% confidence level", this means that ______.

In the equation for the standard deviation of the sampling distribution, $\frac{s}{\sqrt{n}}$ , where s is the standard deviation and n is the sample size, how could one get more precise estimates that differ less from one another?