A survey conducted by a research team was to investigate how the

        A survey conducted by a research team was to investigate how the   education level, tenure in current employment, and age, are related to annual   income. A sample 20 employees is selected and the data is given below.         Education (No. of years) Length of tenure in current employment (No. of years) Age (No. of years) Annual income ($)   17 8 40 124,000   12 12 41 30,000   20 9 44 193,000   14 4 42 88,000   12 1 19 27,000   14 9 28 43,000   12 8 43 96,000   18 10 37 110,000   16 12 36 88,000   11 7 39 36,000   16 14 36 81,000   12 4 22 38,000   16 17 45 140,000   13 7 42 11,000   11 6 18 21,000   20 4 40 151,000   19 7 35 124,000   16 12 38 48,000   12 2 19 26,000   10 6 44 124,000         a. Check if   the F test leads to conclude that an overall regression   relationship exists. If yes, use the t test to determine the   significance of each independent variable. What is the conclusion for each   test at the 0.05 level of significance?   b. Remove   all independent variables that are not significant at the 0.05 level of   significance from the estimated regression equation. What is your estimated   regression equation in this case?