An industrial safety program was recently instituted in the computer chip industry. The average weekly loss (averaged over 1 month) in labor-hours due to accidents in 10 similar plants both before and after the program are as follows:

Determine, at the 5 percent level of significance, whether the safety program has been proven to be effective.

Plant Before After A-B 12 30.5 23 -7.5 18.5 21 2.5 3. 24.5 22 -2.5 4 32 28.5 -3.5 5 16 14.5 -1.5 10 68829 15 15.5 .5 7 23.5 24.5 1 25.5 21 -4.5 28 23.5 -4.5 18 16.5 -1.5