The average life expectancy of tires produced by the Whitney…

The average life expectancy of tires produced by the Whitney Tire Company has been 40,000 miles. Management believes that due to a new production process, the life expectancy of its tires has increased. In order to test the validity of this belief, the correct set of hypotheses is ____________________________________________.

Exhibit 2-1The numbers of hours worked (per week) by 400 sta…

Exhibit 2-1The numbers of hours worked (per week) by 400 statistics students are shown below. Number of hoursFrequency   0 −  9  20 10 − 19  80 20 − 29200 30 − 39100Refer to Exhibit 2-1. The relative frequency of students working 9 hours or less ______________.