Suppose IQ scores were obtained from randomly selected sibli

Suppose IQ scores were obtained from randomly selected siblings. For 20 such pairs of people, the linear correlation coefficient is 0.942 and the equation of the regression line is (caret over) y = 6.25 + 0.97 x, where x represents the IQ score of the older child. Also, the 20x values have a mean of 99.61 and the 20 y values have a mean of 102.6. What is the best predicted IQ of the younger child, given that the older child has an IQ of 107? Use a significance level of 0.05.

The best predicted IQ of the younger child is _______?

Solution

To get the best predicted IQ, we simply plug in the value of x into the regression equation. Here, x = 107. Thus,

y^ = 6.25 + 0.97x

y^ = 6.25 + 0.97(106) = 109.07 [ANSWER]