posted by amanda on .
For the men age 18 and over the avg height was 69 inches with an SD of 3 inches and avg weight was 190 lbs with an SD of 42 pounds. the r value is around 0.41. Estimate the average weight of the men whose heights were 66in, 24 in, and 0in.
Let's gather the data:
Height (x): mean = 69, sd = 3
Weight (y): mean = 190, sd = 42
Correlation: r = 0.41
Regression equation is in this format:
predicted y = a + bx
...where a = intercept and b = slope.
To find the equation, you need to substitute the information given in the problem into a workable formula:
predicted y = (rSy/Sx)X - (rSy/Sx)xbar + ybar
...where r = correlation, Sy = sd of y, Sx = sd of x, and X is the variable in 'a + bx' equation.
Note: xbar = mean of x; ybar = mean of y.
Therefore: predicted y = [(0.41)(42)/(3)]X - [(0.41)(42)/(3)]69 + 190 = 5.74X - 206.06
predicted y = -206.06 + 5.74x
Check the math, then substitute the weights given for x, solving for predicted y.
I hope this will help.