Question

Moving    26   29.9   39.5   25.1   31.6   36.2   25.1   31 35.6   40.

Statics   27.9 29.1 38 27 30.3 34.5 27.8 29.6 33.1 35.5

Continuing the use of the lorry data above,

(a)   Compute the mean and standard deviation for weight in motion.

(b)   Compute the mean and standard deviation for static weight.

(c)   Compute the correlation coefficient (Note: You have already done this in Exercise 06.TR.A. You need only copy it.)

(d)   Use the formulas on pages 199 – 201 of the text to find the slope of the regression line.

(e)   Use these formulas to find the y-intercept of the regression line. (f)   Use the above two results to write the regression equation?

(g)   Check to see that this agrees with the result of part (a) of Exercise 07.BU.A within rounding.

Answer 1

Find X Y . X and Y ? as it was done in the table below. Y 27.9 Y.Y 778.41 846.81 1444 29.1 729 X-Y 725 4 870.09 1501 677.7 957 48 12489 697.78 9176 117836 1420 X X 676 894.01 1560.25 630.01 998 56 1310 44 630 01 961 1267.36 1600 918.09 1190.25 772.84 876.16 1095.61 1260 25 296 33.1 355 Find the sum of every column to get ΣΧ = 320 , ΣΥ 312.8, ΣΧ. Υ = 10194.31, Σx2 - 10527.64, ΣΥ2 - 9911.42 Use the following formula to work out the correlation coefficient η - ΣΧΥ - ΣΧ. ΣΥ γη ΣΧ2 - (ΣΧ)?] - [η ΣΥ? - (ΣΥ)?] 10 - 10194.31 – 320 - 312.8 V10 - 10527.64 - 320?] - [10 - 9911.42 – 312.83] R 0.1663

Find the sum of every column: ΣΧ = 320, ΣΥ = 312.8, ΣΧ.Υ = 10194.31, Σx? - 10527.64 Use the following equations to find a and b. 10 τα ΣΥΣx? - ΣΧ. ΣΧΥ 312.8 - 10527.64 - 320 - 10194.31 η· ΣΧ- (ΣΧ) 10 - 10527.64 - 3202 Η η· ΣΧΥ - ΣΧ. ΣΥ 10 - 10194.31 - 320 - 312.8. - 0.642 η. ΣΧ? - (Σ Χ)? 10 - 10527.64 - (320) Substitute a and bin regression equation formula 9 α + Δ.Σ y = 10.731 + 0.642 -Σ

| (a) Mean = x - 320 = [32] n- 1 X 1. (6) Mean = sy = 312-8 = 31.28] so - 121.036 - 3-754] 10 10-) (c) from the above calculations coooolation coefficieel () +.9663 Slope = 10.642) Y-intercept 10.731 (d) |