A number of investigations have focused on the problem of as

A number of investigations have focused on the problem of assessing loads that can be manually handled in a safe manner. A particular article proposed using a regression model to relate the following dependent variable (y) to k = 3 independent (predictor) variables. y = individual\'s rating of acceptable load (kg) x1 = extent of left lateral bending (cm) x2 = dynamic hand grip endurance (sec) x3 = trunk extension ratio (N/kg) Suppose that the model equation is the following and that = 4.

y = 30 + .90x_1 + .08x_2 - 4.50x_3 + e

(a) What is the mean value of rating of acceptable load when extent of left lateral bending is 30 cm, dynamic hand grip endurance is 190 sec, and trunk extension ratio is 12 N/kg?

18.2

Correct: Your answer is correct.

(b) If repeated observations on rating are made on different individuals, all of whom have the values of x1, x2, and x3 specified in Part (a), in the long run approximately what proportion of ratings will be between 10.2 kg and 26.2 kg? (Use Table 2 in Appendix A. Round your answer to four decimal places.)

I need help on (b), and please explain.

Thank you

Solution