1 A random sample is selected and a confidence interval is c

1. A random sample is selected and a confidence interval is calculated to estimate a parameter. If the confidence level is increased, then the width of the confidence interval will

increase

decrease

remain the same

2. You see a histogram for a data set that has a single peak, is skewed left, and has no apparent outliers. Which of the following is the best conclusion?

the mean and median will be the same

the mean will be greater than the median

the median will be greater than the mean

there will be more than one mode

Solution

1. As the confidence level is increased, the level of significance or the Type 1 error decreases. This increases the width of the confidence interval. Note: 100% confidence interval is the widest.

Answer: increase

2. As the distribution is skewed to the left, it is negatively skewed. Thus,

Mean < Median < Mode

Answer: the median will be greater than the mean