Problem 3-7 Determine a linear trend line for expected freight car loadings. (Ro
ID: 467235 • Letter: P
Question
Problem 3-7
Determine a linear trend line for expected freight car loadings. (Round your intermediate calculations and final answers to 2 decimal places.)
Use the above trend equation to predict expected loadings for Weeks 20 & 21. (Round your final answers to 2 decimal places.)
The manager intends to install new equipment when the volume exceeds 920 loadings per week. Assuming the current trend continues, in which week (at the earliest) should the loading volume reach that level? (Use the rounded answers, as required, from any previous part of this problem. Do not round any other intermediate calculations. Round your final answer to 2 decimal places.)
Explanation / Answer
a). y = 279.80 + 20.99*t
b). Predicted value for week 20 = 279.8 + 20.99*20 = 699.51
Predicted value for week 21 = 279.8 + 20.99*21 = 720.50
c). it should 920 loadings in week number = (920 - 279.8) / 20.99 = 30.51
S. No. x y x*y x2 1 1 340 340 1 2 2 345 690 4 3 3 350 1050 9 4 4 345 1380 16 5 5 350 1750 25 6 6 355 2130 36 7 7 405 2835 49 8 8 445 3560 64 9 9 485 4365 81 10 10 480 4800 100 11 11 520 5720 121 12 12 560 6720 144 13 13 565 7345 169 14 14 570 7980 196 15 15 620 9300 225 16 16 625 10000 256 17 17 630 10710 289 18 18 635 11430 324 171 8625 92105 2109 Regression Equation : Y = a + b*x, where x = independent variable horsepower Y = dependent variable mpg a = intercept point of regression line and y-axis b = slope of regression line N = 18 xy = 92105 x = 171 x2 = 2109 y = 8625 (x)2 = 29241 Slope (b) = N xy - xy 20.986 N x2 - (x)2 Intercept (a) = y - bx 279.80 N Regression Equation : Y = a + b*x, => Y = 279.8 + 20.99 x (rounded to 2 decimal placesRelated Questions
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