30. Determine a linear trend equation Classes f 10 up to 20 2 20 up to 30 1 30 up to 40 4 1 2 2 3 4 2 *15=30 1 *25=25 4 *35=140 10-<20 2 20 -<30 1 30-<40 4 Mean (1+2+2+3+4)/5 Mode Central Tendency 10-<20 2 20-<30 3 30-<40 7 L=(N+1)/2 (7+1)/2=4 Median
50. Determine a linear trend equationY Axis: Dependent Variable Standard Error r2 = 1 r = -1 Standard Error = 0 7 6 5 4 3. 2 1 r2 = 0.24 r = -0.49 Standard Error = 2.5 Individual values are more scattered from the regression line. X Axis: Independent Variable 1 2 3 4 5 6 7
64. Determine a linear trend equationThe graph is positive. X There is a strong determination. X It is a srong positive correlation. X r =0.8619 so 86.19% of the variation in Y is explained by the variation in X. X r2=1.05 r = √ 1.05 = 1.025 = $1.025 X
135. Determine a linear trend equationŶ = a + bt Example: The sales of Jensen Foods, a small grocery chain located in southwest Texas, since 2005 are: a = Y - bX
145. Determine a linear trend equationŶ = 6.1 + 1.3t Example: The sales of Jensen Foods, a small grocery chain located in southwest Texas, since 2005 are:
161. Hint Ŷ = a + bt Step 1 Code the year Step 2 Calculate X*Y, X2 a = Y - bX Step 3 Step 5 Formulate the least square equation What is the b? Ŷ = ? + ?*t Step 4 What is the a? P152 N6 Ch16