A sample of river water is divided into two specimens. One is randomly selected to be sent to Lab A and the other is sent to Lab B. This is repeated for a total of nine times. The measurement of suspended solids at Lab B is subtracted from that of Lab A to obtain the differences

(a) Is there strong evidence that the mean difference is not zero? Test with α = .02.
(b) Construct a 90% confidence interval for the mean difference of the suspended solids measurements.

Transcribed Image Text:

12 10 15 42 4 2 10-7