Question

3) A social psychologist examining whether length of court trials (X) predicts length of time for juries to come to a decision (), reports the following results for the first four trials studied 17 10 Compute the method of least squares to find the equation of the regression line, Step 1: Preliminary Calculations- Fill in the table below. (4 points) Age of Age of Deviation Deviation Deviation Criminal Victim Scores Squared X Scores Y Products of Deviation Scores Y X2M (X 2 M YOM, (X-M Y -M) . 1

Answer 1

DATE: PAGE NO.: Stebi: Age of criminal Age of victim Deration Scores' Dersation Squared x (X-Mx) -31 Ooo (x-mx) ² 961 361 -19 -2.8 TH --30 900 M = 36 Ssx= 3006 Dersation scores Poroducts of Dunication swres - (x-mx) (4- My) (4- My) - 20 - 18 620 342 616 N 720 2297 Step 2: To find slope : Regression Formula : 4 = a + 6x where slope b = {(x-Mx) (y My). I E (x-3) 2 2 b 2298 = 0.7645" 3006

DATE PAGE NO.: Slope , b = 0.7645 Step 3: y-interupt: bx = My - ьму = 28- (0.7045)x3 6 = 28 - 27.522 = 0.478 a= 0.478 Step Formula for regression line : Equation of line of regression of 4 or Xis: 4- ý = rty (x-x) where = wrrelation wefficient - 4 = Me an of 4 x = Mean of x Ty Te - Standard deviations of y. anda resp. Similarly, equation of line of regression of x on y is : - x - x = r Tx (4-9)