1. As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution

a.becomes smaller.

b.stays the same.

c.becomes larger.

d.fluctuates.

2. In order to estimate the average time spent per studenton the computer terminals at a local university, data were collected for a sample of 64 business students over a one-week period. Assume the population standard deviation is 1.6 hours.If the sample mean is 9 hours, then the 95% confidence interval is _____ hours.

a.8.61 to 9.39

b.8.18 to 8.92

c.8.78 to 9.58

d.8.35 to 9.11

3. A study to determine the average study time per student was conducted at a university. Data was collected from a sample of 72 students over a two month period. The population standard deviation was known to be 5.6 hours. What is the margin of error with a 96% probability?

a.0.79

b.1.355

c.1.29

d.0.66