Question 1: Carry out multiple linear regression of strength on height and age. What is the equation and what can we conclude?
Click Analyze, Regression, Linear. Select Quadriceps strength into Dependent and Height and Age into Independents(s). Click OK.
You will get four tables of output, of which the last is
| Coefficients(a) | ||||||
|---|---|---|---|---|---|---|
| Model | Unstandardized Coefficients | Standardized Coefficients | t | Sig. | ||
| B | Std. Error | Beta | ||||
| 1 | (Constant) | -465.626 | 460.333 | -1.011 | .318 | |
| Height (cm) | 5.398 | 2.545 | .314 | 2.121 | .040 | |
| Age (years) | -3.075 | 1.467 | -.311 | -2.096 | .043 | |
| a. Dependent Variable: Quadriceps strength (newtons) | ||||||
The multiple regression equation is:
strength = −466 + 5.40 × height − 3.08 × age
I have given all the coefficients to three significant figures.
We can conclude that, for men of any given age, men taller by one centimetre will have greater mean strength by an estimated 5.40 newtons, and, for men of any given height, men older by one year will have lower mean strength by an estimated 3.06 newtons. There is evidence that relationships of strength with both height and age are present in the population from which these men were drawn.
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Last updated: 21 February, 2012.