Inferential statistics is so named because it allows us to examine a sample and make inferences about ____________________

A. another sample.

B. an element of the sample.

C. the population from which the sample was taken.

D. none of the above.

It is the value that separates the rejection region from the non-rejection region.

A. Parameter

B. Critical Value

C. Test Statistic

D. Significance Level

Suppose we wish to test H0: 53 vs Ha: >53. What will result if we conclude that the mean is greater than 53 when in fact the true value of the mean is 50?

A. We have committed a Type I error.

B. We have made a correct decision based on the test.

C. We have committed a Type II error.

D. None of the above.

Data on the time an online banking transaction is completed, gathered from 400 randomly selected online banking transactions produced the following summary statistics: x =21.3 seconds; s=1.7 seconds. At least what proportion of the data lies within 2 3/4 standard deviations from the mean?

A. 20%

B. 72.6%

C. 86.8%

D. 91%

The t - distribution is similar to the standard normal distribution in the following ways except:

A. The spread of the t - distribution varies, depending on the degrees of freedom.

B. It is symmetrical about the mean.

C. The mean, median, and mode are all equal to zero and are located at the center of the distribution.

D. The curve is bell-shaped and is asymptotic to the horizontal axis.

What is the area under the standard normal curve between z = -1.79 and z = 1.79?

A. 0.0734

B. 0.0802

C. 0.9265

D. 0.9633

Suppose for 40 observations the variance is 50. If all the observations are increased by 20, the variance of these increased observations will be

A. 2.5

B. 50

C. 70

D. 400

What is the area under the standard normal curve between z = -1.0 and z = -2.0?

A. 0.0228

B. 0.1359

C. 0.3413

D. 0.4772