Height is frequently named as a good predictor variable for weight among people of the same age and gender.
Problem: Height is frequently named as a good predictor variable for weight among people of the same age and gender. The following are th e raw data and results of a regression analysis of the heights and weights of a sample of 14 males between the ages of 19 and 26 who participated in a study.
Answer the following
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Write out the regression equation.
Solution: Using SPSS and the data provided we obtain the following output:
From the last table, we get the following regression equation:
\[\hat{W}=-60.622+0.755\,H\]
where \(\hat{W}\) represents the estimated weight and \(H\) represents the height. -
If you knew that the height of someone was 162.5, calculate the weight of that person.
Solution: We use the regression equation to the predicted weight. We simply plug \(H=162.5\) into the last equation, which gives the following estimated weight
\[\hat{W}=-60.622+0.755\times 162.5=62.0655\] - What information do you look at in the output to determine whether there is a statistically significant relationship between height and weight in this sample?
Solution: We look at the following table:
We are interested in \(R\) and \({{R}^{2}}\). The value \(R=0.689\) indicates a significant linear relationship between height and weight (for this \(R\) we reject the hypothesis that the actual correlation is zero). But in spite of the fact there a linear relationship, it’s not too strong. The value of \({{R}^{2}}=0.475\) implies that only 47.5% of the variation of the weight is explained by the linear regression.
HEIGHT (cm)
WEIGHT ( kgs )
185 83.9
180 99.0
173 63.8
168 71.3
175 65.3
183 79.6
184 70.3
174 69.2
164 56.4
169 66.2
205 88.7
161 59.7
177 64.6
174 78.8
Deliverable: Word Document
