A computer service company which employs thousands of
phone-technicians did a study in which researchers interviewed
technicians to assess if they were experiencing back pain at their
monitor. For the 128 people suffering from back pain while sitting
at their monitors that were utilized, each was given a “new†chair
identical in every visible aspect to their old chair except in
color. Secretly, 64 of the recipients were randomly chosen to
receive a chair with the seat cushion containing a “gel†center,
while the others received the same “old†chair. After three weeks,
20 of the people with the “gel†seats reported having reduced back
pain compared to only 12 of those having the “regular†seats.
For all confidence intervals, include
a. difference between sample estimates
b. standard error c. confidence interval
d. State if you can conclude a difference, if so which one is
greater
