For items 31 to 33: Some managers of companies use employee rankings to laud the best and let go of the worst. Suppose the distribution of rankings of employees at a large company is normal with a mean of 65 points and a standard deviation of 6 points.

31. What proportion of employees has a ranking above 59 points?

A. 0.1587

B. 0.3413

C. 0.6587

D. 0.8413

32. Managers of this large company were told to determine the top 20%, bottom 10% and the remaining 70% in the middle, then let go those in the bottom tier. Using the provided model for rankings, what is the cut-off ranking points for an employee to be in the top 20%?

A. 20.00

B. 57.31

C. 70.05

D. 80.00

33. Using the model for rankings, what is the cut-off for the company to let go of an employee?

A. 10.0

B. 57.31

C. 70.05

D. 80.00

A cereal company claims that the mean weight of the cereal in its packets is 14 oz. Assuming that a hypothesis test of the claim was conducted and that the null hypothesis is rejected, what would be the conclusion?

A. The mean weight of packets of cereal is less than 14 oz.

B. The mean weight of packets of cereal is greater than 14 oz.

C. The mean weight of packets of cereal is 14 oz.

D. The mean weight of packets of cereal is not 14 oz.

When the population standard deviation is unknown or not given for a hypothesis test, the test statistic to use is the

A. normal distribution.

B. z - statistic.

C. t - statistic.

D. p - value.

The null and alternative hypotheses are statements made about

A. population parameters.

B. sample parameters.

C. sample statistics.

D. either A or C.

In a hypothesis test, a Type II error occurs when

A. the null hypothesis is not rejected when the null hypothesis is true.

B. the null hypothesis is rejected when the null hypothesis is true.

C. the null hypothesis is not rejected when the alternative hypothesis is true.

D. the null hypothesis is rejected when the alternative hypothesis is true.

Suppose we wish to test Ho: ? ? 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 55?

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.

34. It denotes the probability of committing a Type ll error. a A. OB. O O c. OD