14.The following data was collected from a simple random sample of a population of college freshmen. It represents their ages on the first day of the fall semester.

17 21 19 18 18 19

The point estimates of the population mean and standard deviation are:

1. 18 and 1.75.
2. 19 and 1.78.
3. 17.67 and 1.63
4. .18.67 and 1.36

15.The Office of Student Services at a large western state university maintains information on the study habits of its full-time students. Their studies indicate that the mean amount of time undergraduate students study per week is 20 hours. The hours studied follows the normal distribution with a standard deviation of six hours. Suppose we select a random sample of 144 current students. What is the probability that the mean of this sample is less than 19.25 hours?

1. 0.4332
2. 0.8664
3. 0.0668
4. 0.0181

16.For a population that is not normally distributed, the distribution of the sample means will ________.

1. Be negatively skewed
2. Approach a normal distribution
3. Be positively skewed
4. Take the same shape as the population

17.When all the items in a population have an equal chance of being selected for a sample, the process is called _________________.

1. simple random sampling
2. z-score
3. sampling error
4. nonprobability sampling

18.Suppose we select every fifth invoice in a file. What type of sampling is this?

1. Random
2. Cluster
3. Stratified
4. Systematic

19.Which of the following is the standard error of the mean?

?

x