(Use Excel) An engineer wants to determine the effectiveness of a safety program. He collects annual loss of hours due to accidents in 12 plants "Before and After" the program was put into operation.

PlantBeforeAfterPlantBeforeAfter

1125 108 7 96 109 2118 83 8 91 87 3123 100 9 77 64 498 83 10 62 68 574 61 11 87 53 6110 81 12 109 107

Click here for the Excel Data File

Let the difference be defined as Before - After.

a.Specify the competing hypotheses that determine whether the safety program was effective.

H₀: μ_D = 0; H_A: μ_D ≠ 0H₀: μ_D ≤ 0; H_A: μ_D > 0H₀: μ_D ≥ 0; H_A: μ_D < 0

b.Using the appropriate commands in Excel, calculate the value of the test statistic. Assume that the hours difference is normally distributed. (Round intermediate calculations to at least 4 decimal places and final to 2 decimal places.)

Test statistic  

c. At the 5% significance level, specify the critical value(s). (Round your answer to 3 decimal places.)

Critical value  

d. Is there sufficient evidence to conclude that the safety program was effective? Yes, since we reject H₀No, since we do not reject H₀Yes, since we do not reject H₀No, since we reject H₀