21-2 It is decided to develop standard data for the job of washing windows in a condominium apartment building. These data will be expressed in terms of standard times, because the allowance factor will be constant for all such jobs.

In any case, four stopwatch time studies are made of an individual washing windows of various sizes. The activity involves a number of elements, one of which is "Dry window using a 12-inch squeegee." The analyst correctly assumes that the time required for this element will depend on the size of the window. He begins the determination of the relationship between these two variables by listing the calculated standard times and the corresponding window sizes. The results are as follows:

Standard Window time, min area, sq ft 0.61 16 0.35 8 0.82 24 0.39 12 a What is the value of the coefficient of correlation for the two variables as determined with the use of Eq. (2-8)? (Ans. 0.98)
b What is the equation of the least-squares line, as determined with the use of Eqs. (2-4) and (2-5), which serves to describe the relationship between the variables? (Ans. Y' = 0.0745 + 0.03 12*)
c Construct a graph which describes the relationship between the two variables.
d Prepare a table which describes the relationship between the two variables.
Do this by beginning with a window area of 8 square feet and increasing the value of the area in steps of 1 square foot until a maximum of 24 square feet is reached.