Question

Group	Mean x	Standard deviation s	Sample size n
Female	0.9	.9764	7
Male	6.9667	8.899	21

Consider the confidence interval 99% (lower, upper) (-11.6634,-.47), and indicate whether each of the following statements below is correct or incorrect interpretations of this interval.

a. A 90% confidence interval calculated from the same data would be wider than the interval already computed. (True or False)

b. There is a 99% chance that the true difference in RDI Levels between men and women is contained in the interval already computed. (True or False)

c. In repeated samples, approximately 99% of all differences in sample means will fall within the bounds of the interval already computed. (True or False)

d. We can be 99% confident that the true difference in mean RDI levels between men and women is contained within the bounds of the interval already computed. (True or False)

Answer 1

Since critical value for 90% confidence interval is smaller for critical value for 99% CI so 90% confidence interval will be narrower.

In repeated samples, approximately 99% of all confidence intervals will contain true differences in population mean.

a. A 90% confidence interval calculated from the same data would be wider than the interval already computed.

Answer: False

b. There is a 99% chance that the true difference in RDI Levels between men and women is contained in the interval already computed.

Answer: True

c. In repeated samples, approximately 99% of all differences in sample means will fall within the bounds of the interval already computed.

Answer: False

d. We can be 99% confident that the true difference in mean RDI levels between men and women is contained within the bounds of the interval already computed.

Answer: True