(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.

PlantBeforeAfterPlantBeforeAfter112510879610921188389187312310097764498831062685746111875361108112109107

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:_D= 0;H_A:_D 0H₀:_D 0;H_A:_D> 0H₀:_D 0;H_A:_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 rejectH₀No, since we do not rejectH₀Yes, since we do not rejectH₀No, since we rejectH₀