Chapter 9 Quiz

When n is small (less than 30), how does the shape of the t distribution compare to the normal distribution? -It is almost perfectly normal. -It is flatter and more spread out than the normal distribution. -There is no consistent relationship between the t distribution and the normal distribution. -It is taller and narrower than the normal distribution.

It is flatter and more spread

A sample of n = 25 scores produces a t statistic of t = -2.062. If the researcher is using a two-tailed test, which of the following is the correct statistical decision? -The researcher can reject the null hypothesis with either alpha = .05 or alpha = .01. -It is impossible to make a decision about H0 without more information. -The researcher can reject the null hypothesis with alpha = .05 but not with alpha = .01. -The researcher must fail to reject the null hypothesis with either alpha = .05 or alpha = .01.

The researcher must fail to reject the null hypothesis with either alpha = .05 or alpha = .01.

Which of the following is not needed to compute a t statistic? -The value of the sample variance or standard deviation -A hypothesized value for the population mean -The value of the sample mean -The value of the population variance or standard deviation

The value of the population variance or standard deviation

Which of the following samples will have the smallest value for the estimated standard error? Note: s2 below refers to s2 n= 16 with s2 = 64 n = 4 with s2 = 64 n = 4 with s2 = 16 n = 16 with s2 = 16

n = 16 with s2 = 16

A researcher conducts a hypothesis test using a sample from an unknown population. If the t statistic has df = 30, how many individuals were in the sample? Cannot be determined from the information given n = 30 n = 31 n = 29

n = 31

What is the sample variance and the estimated standard error for a sample of n = 9 scores with SS = 72? s2 = 3 and sM = 1 s2 = 9 and sM = 3 s2 = 3 and sM = 3 s2 = 9 and sM = 1

s2 = 3 and sM = 1

With a = .01, the two-tailed critical region for a t test using a sample of n = 16 subjects would have boundaries of ______. t = ±2.602 t = ±2.921 t = ±2.583 t = ±2.947

t = ±2.947