9.

In a z test, the z ratio indicates how many __________units the sample mean deviates from the hypothesized population mean.

A)

standard error

B)

Original

C)

Critical

D)

significance level

10.

An investigator claims, with 95 percent confidence, that the interval between 10 and 16 miles includes the mean one-way commute distance for all California commuters. To have 95 percent confidence signifies that

A)

the unknown population mean is between 10 and 16 miles with probability .95.

B)

if these intervals were constructed for a long series of samples, approximately 95 percent would include the unknown mean commute distance for all Californians.

C)

if sample means were obtained for a long series of samples, approximately 95 percent of all sample means would be between 10 and 16 miles.

D)

the unknown population mean is definitely between 10 and 16 miles.

11.

When sample size is sufficiently large, about ______ percent of all sample means are within one standard error of the sampling distribution mean.

A)

100

B)

95

C)

50

D)

68

12.

The central limit theorem concentrates on changes in the ________________ of a sampling distribution.

A)

Variability

B)

central tendency

C)

Size

D)

Shape