Question

1. To estimate the standard error of the mean, a survey researcher will:

Select one:

a. take the square root of the sample standard deviation.

b. none of the above.

c. multiply the sample standard deviation times the square root of the sample size.

d. divide the sample standard deviation by the square root of sample size.

2. Suppose that a business researcher is attempting to estimate the amount that members of a target market segment spend annually on detergent and wants to use a Z-value of 1.96.  If past research studies with this target market segment have shown that the standard deviation for this type of study was approximately $3.12, approximately what sample size should the researcher use if he wants an error of plus or minus $0.50?

Select one:

a. 150

b. None of the above

c. 50

d. 100

3.

A researcher conducts a survey and calculates the confidence interval to be between 400 and 440 at the 95 percent confidence level. This means that:

Select one:

a. There is a 90 percent probability that the sample mean will fall in this range.

b. There is a 100 percent probability that the population mean will fall in this range

c. If 100 samples were conducted, 5 times out of 100 the sample mean would fall within the confidence interval that was calculated

d. If 100 samples were conducted, 95 times out of 100 the true population mean would fall within the confidence interval that was calculated.

4.

If you wish to estimate the mean of a particular population, doubling the range of acceptable error will reduce sample size to       its original size.

Select one:

a. It cannot be determined

b. one fourth

c. twice

d. one half

Answer 1

(1)

Correct option:

d.     divide the sample standard deviation by the square root of sample size.

Explanation:

(2)

Correct option:

a.   150

Explanation:

Given:

Z = 1.96

= 3.12

e = 0.50

Sample Size (n) is given by:

(3)

Correct option:

d. If 100 samples were conducted, 95 times out of 100 the true population mean would fall within the confidence interval that was calculated.

(4)

Correct option:

b. one fourth

Explanation:

Doubling the width of the confidence interval will reduce the sample size one fourth.