The Professor's Response
Hello Professor disregard the question I just asked " in the homework section 9.8 problem 35 I am not getting the right numbers for the interval. My critical value is 3.106 and the test stat comes out to be 3.16. What am I doing wrong?" my critical value was incorrect now I have the interval [-3.24, 1.24].
See the professor's answer below.
Hi Sheyla,
When I subtract the two rows of data (Reported - Measured), I get an average difference of -1.0.
The data for this problem is then:
n = 12
X-bar = -1.0
S = 3.5196
CL = 0.95
The critical ta/2, df value is: t0.025, 11 = 2.201
This gives us a margin of error of: E = 2.201*3.5196/root(12) = 2.2363.
The final interval is (-1.0 - 2.2363, -1.0 + 2.2363) = (-3.2363, 1.2363).
**note: if I had done my subtraction in the other order, I would have the answer: (-1.2363, 3.2363).
I hope this answers your question,
Professor McGuckian