A researcher would like to estimate how much difference in cigarette smoking results from viewing graphic videos (including an autopsy) on the harmful effects of smoking. A sample of 16 smokers is obtained. Half of the smokers (n = 8) view the video and the other half (n = 8) serves as a control group. The number of packs of cigarettes each person smoked during the following week is recorded. The data are as follows:

Controls: M = 17.5, SS = 122

Video Viewers: M = 8.1, SS = 102

Use the sample data to make a point estimate of the mean difference in smoking behavior between the control group and the video viewers.

Point estimate =?

Make an interval estimate of the mean difference so that you are 80% confident that the population mean difference is in your interval.

Estimated standard error = ?

df = ?

Critical t-value = ?

Lower bound of confidence interval = ?

Upper bound of confidence interval =?