1. What is the probability that x is between 3 and 6, given the function below?

f(x) = (1/10) e^-x/10 Forxgreater than or equal to 0

a.

0.1920

b.

0.4512

c.

0.6065

d.

0.2592

2. The ages of students at a university are normally distributed with a mean of 21. What percentage of the student body is at least 21 years old?

a.

1.96%

b.

It could be any value, depending on the magnitude of the standard deviation

c.

21%

d.

50%

3. Use the normal approximation to the binomial distribution to answer this question. Eleven percent of all students at a large university are absent on Mondays. If a random sample of 12 names is called on a Monday, what is the probability that four students are absent?

a.

0.0065

b.

0.9935

c.

0.0285

d.

0.9715

4. Parameters are

a.

numerical characteristics of a sample.

b.

numerical characteristics of either a sample or a population.

c.

numerical characteristics of a population.

d.

the averages taken from a sample.

5. A simple random sample of 100 observations was taken from a large population. The sample mean and the standard deviation were determined to be 1234 and 120 respectively. The standard error of the mean is

a.

12.

b.

1.2.

c.

120.

d.

1234 120.

6. Convenience sampling is an example of _____sampling.

a.

cluster

b.

stratified

c.

probabilistic

d.

nonprobabilistic

7. The closer the sample mean is to the population mean,

a.

the larger the sampling error.

b.

the smaller the sampling error.

c.

the sampling error equals 1.

d.

none of these alternatives is correct.

8. A population has a mean of 300 and a standard deviation of 12. A sample of 64 observations will be taken. The probability that the sample mean will be between 295 to 305 is

a.

0.3231.

b.

0.9991.

c.

0.0009.

d.

0.6769.

9. A sample of 66 observations will be taken from an infinite population. The population proportion equals 0.12. The probability that the sample proportion will be less than 0.1969 is

a.

0.9727.

b.

0.0273.

c.

0.9045.

d.

0.0955.

10. The purpose of statistical inference is to provide information about the

a.

population based upon information contained in the sample.

b.

mean of the sample based upon the mean of the population.

c.

sample based upon information contained in the population.

d.

population based upon information contained in the population.