There have been many studies recently concerning coffee drinking and cholesterol level. While it is known that several coffee-bean components can elevate blood cholesterol level, it is thought that a
new type of paper coffee filter may reduce the presence of some of these components in coffee.
The effect of the new filter on cholesterol level will be studied over a 10-week period using 300
nonsmokers who each drink 4 cups of caffeinated coffee per day. 150 participants are randomly
assigned to the experimental group, who will only drink coffee that has been made with the new
filter, with remaining participats assigned to the control group, who will only drink coffee that has
been made with the standard filter. Each participant's cholesterol level will be measured at the
beginning and at the ind of the study to determine if there was an increase in cholesterol level.
The table summarizes the result of the experiment:
New Filter
Old Filter
Increase in Cholesterol
62
84
No Increase in Cholesterol
88
66 -

a.
Does the data provide enough evidence to conclude that the new filter does a better job with
cholesterol?

b.
Estimate the difference in proportions for the effect on cholesterol for the two filters.