Statistics class: Comparing two means.

Work excercise:

A study of the effect of exposure to color ( red or blue) on the ability to solve puzzles used 38 subjects. Half the subjects were asked to solve a series of puzzles while in a red-colored environment. The other half were asked to solve the same series of puzzles while in a blue-colored environment. The 19 subjects in the red-colored environment had a mean time for solving the puzzles of 9.66 seconds with standard deviation 3.42 ; the 19 subjects in the blue-colored environment had a mean time of 15.87 seconds with standard deviation 8.62 .

What is the value of The two-sampletstatistic for comparing the population means (

0.001) _____