1. In a survey concerning electronic monitoring and surveillance, it was found that 112 of 320 businesses fired worker for misuse of the Internet, and 225 of 750 businesses fired workers for email misuse..

a) Construct and interpret a 95% confidence interval for the proportion of businesses that have fired workers for misuse of the Internet. (2)

b) Construct a 90% confidence interval for the proportion of businesses that fired workers for email misuse. (2)

2. A consumer magazine contacted a random sample of 33 owners of a certain car model and asked each owner how many defects had to be corrected within the first 2 months of ownership. The average number of defects was 3.7, with a standard deviation of 1.8 defects.

a) Determine a 90% confidence interval for the true mean number of defects for this car model. (2)

b) Determine a 95% confidence interval for the true mean number of defects for this car model. (2)

c) Determine a 99% confidence interval for the true mean number of defects for this car model. (2)

d) Find the length of the confidence intervals. What do you observe about the width of the confidence interval as the level of confidence increases? (2)