A study was made by a department store to determine the relationship between weekly sales and advertising expen- ditures. The following data were recorded Predict the sale value if the advertising cost is & thorand was Advertising Cost Sales (in thousand pesos) (in thousand pesos) X Y 4.0 38.5 2.0 40.1 2.5 39.5 2.0 36.5 50 440 5.5 $5.0 20.5 30 415 420 48:0 N10. The following data represent the operating time in hours for 4 types of pocket calculators before a recharge is required. Fx101 Fx202 Fx303 Fx404 7.1 53 61 58 71 49 65 50 7.2 6.1 6.2 5.1 7.3 7.1 50 40 Use the at the Of level of significance. Test the hypothesis that the operating times for all four calculators are equal *Assume that the data are not normally distributed