Question

Using an alpha = 0.05 a confidence interval for a population mean is determined to be 3.65 to 3.75. If the level of significance is decreased, the interval for the population mean

Select one:

a. becomes narrower

b. becomes wider

c. does not change

d. increases or decreases depending on the value of the population mean

Answer 1

If significance level decresed, it requires higher accuracy for population mean to fit in the

confidence interval.

For example- for 0.05 significance level, we are 95% confident that population parameter contains in

confidence interval.

if significance level decreased to 0.01 (say) Then we are 99% confident that population parameter contains in

confidence interval,.

As significance level decresed, confidence level for population mean to fit in interval increased.

For this reason, the interval for population mean becomes wider.