Question

Ask 3 people, whose height and shoe length you have not used to prepare the graph, for their height and shoe length. Then see how accurately your line predicts what their shoe length should be. Do this by physically (print out graph) or virtually (use graph on computer) finding each person's height on the vertical axis (y-axis) of your trend line plot and then draw or follow a line straight across to the right until you intersect the trend line on the graph. Drop down a straight line to read the predicted shoe length from the horizontal axis (x-axis) directly below the point of intersection. Prepare a table, and only a table, comparing the 3 people’s height, predicted shoe length, and actual shoe length.

Answer 1

I am using a dummy data of 20 men's height and shoe length. Shoe length is our predictive variable and height is our independent variable.

excel data (measured in inches)

Height (X)	Shoe length (y)
68	12
66	9
75	12
71	11
67	12
65	8.5
67	9
75	13
72	11
74	12
72	12
75	12
69	10
70	11
65	10
64	8
68	9
73	11
70	8
76	12

Chart is prepared in excel

The regression equation is

Y = 0.3004x - 10.433

slope =0.03004 and y-interept = -10.433

New data

Heigth	Shoe length Actual	Shoe length predicted
66	10	9.3934
64	13	8.7926
72	12	11.1958

The predicted shoe length is found by subsituting corresponding Heights in the the formula

Y = 0.3004x - 10.433

Apologies I couldn't plot both lines on one chart.

looking at both the charts we can see that both trendlines would overlap each other.