Question 1

Amina wants to determine the sample size necessary to adequately conduct a study to estimate the population mean to within 3.2 points. The range of population values is 76 (note that SD = range/4) and the researcher plans to use a 99% level of confidence. The sample size should be at least:

Select one:

a. 136

b. 95

c. 235 

d. 192

Question 2

Lauren Graham, Executive Manager with Global Financial Service (GFS), is studying employee use of GFS email for non-business communications. She plans to use a 90% confidence interval estimate of the proportion of email messages that are non-business; she will accept a 0.06 error. Previous studies indicate that approximately 20% of employee email is not business related. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 120

b. 242 

c. 171

d. 296

Question 3

In estimating sample size, if the population standard deviation is unknown, it can be estimated by using:

Select one:

a. one-half of the range

b. one-fourth of the range 

c. the population mean

d. the z-score

Question 4

Julian wants to conduct a study to estimate the population mean. She plans to use a 95% level of confidence to estimate the mean, and the population standard deviation is approximately 42. Julian wants the error to be no more than 5. The sample size should be:

Select one:

a. 272 

b. 190

c. 194

d. 470

Question 5

George wants to conduct a study to estimate the population mean. He plans to use a 95% level of confidence to estimate the mean, and the population standard deviation is approximately 34. George wants the error to be no more than 4. The sample size should be:

Select one:

a. 178

b. 278 

c. 194

d. 392

Question 6

Hudson seeks to calculate the sample size necessary to adequately conduct a study to estimate the population mean to within 2 points. The range of population values is 72 (note that SD = range/4) and the researcher plans to use a 90% level of confidence. The sample size should be at least:

Select one:

a. 312

b. 540

c. 218 

d. 440

Question 7

An Australian researcher wants to conduct a study to estimate the population mean. He plans to use a 90% level of confidence to estimate the mean, and the population standard deviation is approximately 38. The researcher wants the error to be no more than 3. The sample size should be:

Select one:

a. 732

b. 1068

c. 616

d. 432 

Question 8

Jessica Round, a branch Manager with Rocky Fashions, is studying employee use of company email for non-business communications. She plans to use a 99% confidence interval estimate of the proportion of email messages that are non-business; she will accept a 0.04 error. Previous studies indicate that approximately 33% of employee email is not business related. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 751

b. 920

c. 531 

d. 372

Question 9

James Weepu, Human Resources Manager with Auckland First Bank (AFB), is reviewing the employee training programs of AFB branches. He plans to use a 95% confidence interval estimate of mean training time of tellers and is willing to accept an error of 1 hour; previous studies indicated a standard deviation of 2 hours. The sample size should be at least _______.

Select one:

a. 68

b. 19

c. 34

d. 16 

Question 10

Maddison wants to estimate a population proportion with a 90% level of confidence. From previous studies she estimates that the population proportion is no more than .40. The researcher wants the estimate to have an error of no more than .04. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 577

b. 815

c. 999

d. 404 

Question 11

Suppose a population has a mean of 90 and a standard deviation of 28. If a random sample of size

49 is drawn from the population, the probability of drawing a sample with a mean between 80 and 100

is _______.

Select one:

a. 0.0124.

b. 0.0062.

c. 0.4938.

d. 0.9876. 

Question 12

Salem, a soccer coach, is examining the player motivational programs. He plans to use a 90% confidence interval estimate of mean motivational training time and is willing to accept an error of 0.5 hour; previous studies indicated a standard deviation of 1 hours. The sample size should be at least _______.

Select one:

a. 16

b. 17

c. 11 

d. 27

Question 13

A researcher wants to conduct a study to estimate the population mean. He plans to use a 98% level of confidence to estimate the mean, and the population standard deviation is approximately 30. The researcher wants the error to be no more than 3. The sample size should be:

Select one:

a. 194

b. 269

c. 278

d. 543 

Question 14

Maxim wants to estimate a population proportion with a 99% level of confidence. From previous studies he estimates that the population proportion is no more than .36. The researcher wants the estimate to have an error of no more than .02. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 3835

b. 2213

c. 3128

d. 1550

Question 15

A researcher wants to estimate a population proportion with a 90% level of confidence. From previous studies she estimates that the population proportion is no more than .30. The researcher wants the estimate to have an error of no more than .02. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 2851

b. 2017

c. 1413 

d. 3495

Question 16

Julia wants to estimate a population proportion with a 95% level of confidence. From previous studies she estimates that the population proportion is no more than .25. The researcher wants the estimate to have an error of no more than .03. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 1387

b. 561

c. 1132

d. 801 

Question 17

Camelia plans to estimate the sample size necessary to adequately conduct a study to estimate the population mean to within 2 points. The range of population values is 68 (note that SD = range/4) and the researcher plans to use a 98% level of confidence. The sample size should be at least:

Select one:

a. 278

b. 195

c. 481

d. 393 

Question 18

A researcher at Capstone Pharmaceuticals wants to determine the sample size necessary to adequately conduct a study to estimate the population mean to within 5 points. The range of population values is 80 (note that SD = range/4) and the researcher plans to use a 90% level of confidence. The sample size should be at least:

Select one:

a. 107

b. 62

c. 44 

d. 87

Question 19

Mr. Loch, Human Resources Manager with KT International, is reviewing the employee training programs of various branches. He plans to use a 95% confidence interval estimate of mean training time and is willing to accept an error of 1.5 hour; previous studies indicated a standard deviation of 6 hours. The sample size should be at least _______.

Select one:

a. 44

b. 62

c. 107

d. 87

Question 20

Brian wants to estimate a population proportion with a 98% level of confidence. From previous studies he estimates that the population proportion is no more than .20. The researcher wants the estimate to have an error of no more than .05. The necessary sample size is at least (please, use the formula determining sample size when estimating p):

Select one:

a. 348 

b. 427

c. 246

d. 173