Complete Chapter 4 problems 67 and 78 from page 204 and 206 at the end of the chapter. Refer to the associated files: P04_67.xlsxfor problem 67 and P04_78.xlsxfor problem 78.. Each year the employees at Zipco receive a $0, $2000,or $4500 salary increase. They also receive a meritrating of 0, 1, 2, or 3, with 3 indicating outstandingperformance and 0 indicating poor performance. Thejoint probability distribution of salary increase andmerit rating is listed in the file P04_67.xlsx. Forexample, 20% of all employees receive a $2000increase and have a merit rating of 1. Find the correlationbetween salary increase and merit rating. Theninterpret this correlation.78. A manufacturing plant produces two distinct products,A and B. The cost of producing one unit of A is $18and that of B is $22. Assume that this plant incurs aweekly setup cost of $24,000 regardless of the numberof units of A or B produced. The means and standarddeviations of the weekly production levels of A and Bare given in the P04_78.xlsx.a. Assuming that the weekly production levels of Aand B are independent, find the mean and standarddeviation of this plant’s total weekly productioncost. Between which two total cost figures can yoube about 68% sure that this plant’s actual totalweekly production cost will fall?b. How do your answers in part a change if youdiscover that the correlation between the weeklyproduction levels of A and B is actually 0.29?Explain the differences in the two sets of results.