The 21 subjects in the red-colored environment had a mean time for
solving the puzzles of 9.64 seconds with standard deviation 3.43; the
21 subjects in the blue-colored environment had a mean time of 15.84
seconds with standard deviation 8.65. The two–sample t statistic for
comparing the population means has value
• (a) 1.50.
• (b) 3.05.
• (c) 6.2.
Coaching and SAT scores
19.26 Coaching and SAT scores, continued. What we really want to know is whether
coached students improve more than uncoached students, and whether any
advantage is large enough to be worth paying for. Use the information in the previous
exercise to answer these questions:
(a) Is there good evidence that coached students gained more, on the average, than
Hint: H0: μ1 = μ2, Ha: μ1 > μ2
Calculate two–sample t statistic:
Df = ?
Using Table C find the p-value