Question

1. You are trying to see if there is a relationship between height and weight. Write down the following data, then by using a software program (e.g., Excel and SPSS), find the correlation between the following data:

Height: 5' 11", 6' 2", 4' 3", 5' 5", 6' 6", 5' 2", 5' 9"

Weight: 175, 190, 102, 150, 210, 130, 160

a. Using the above data, find the regression equation using weight as the dependent variable and height as the independent (predictor) variable. What is it?

b. If someone is 6'0" tall, how much do you think he would weigh? If someone was 4'10" tall, what would her estimated weight be?

c. Is the correlation strong, moderate or weak?

2. Input the following data and calculate the correlation after guessing what it might be.

Body fat %: 15, 17, 14, 15, 16, 17, 15, 16, 15

Height: 72", 55", 66", 59", 78", 70", 59", 62", 52"

a. Create a scattergraph of the above data using body fat % as the y variable and height as the x variable. Before doing this, however, predict what the data will look like on the graph.

b. Create a regression line of best fit for the above data. Does the regression line confirm your predictions?

c. Simply by looking at the regression line, guess what someone's body fat % is if the person was 60" tall. Then calculate the value using the regression equation. Were the values similar?

d. Is the correlation strong, moderate or weak?

Answer 1

First, we have to convert height to decimal form

X	5.92	6.17	4.25	5.42	6.50	5.17	5.75
Y	175	190	102	150	210	130	160

a)

X	Y	X.Y	X.X
5.92	175	1036	35.0464
6.17	190	1172.3	38.0689
4.25	102	433.5	18.0625
5.42	150	813	29.3764
6.50	210	1365	42.25
5.17	130	672.1	26.7289
5.75	160	920	33.0625

The regression Line is

b)

At x=6, y will be

Y=-111.659+48.459*6=179.095

At x= 4'10" = 4.83

Y=-111.659+48.469*4.83=122.446

C)

High Correlation