# Refer to Exercise 19.14. The histogram of the residuals and the graph of the residuals and the…

Refer to Exercise 19.14. The histogram of
the residuals and the graph of the residuals and the predicted values are shown
below.

a Does it appear that the normality
requirement is violated? Explain.

b Is the error variable variance constant? Explain.

XR19-14 Suppose that the statistics
practitioner who did the analysis described in Exercise 18.21 wanted to
investigate other factors that determine height. As part of the same study, she
recorded the heights of the mothers in column 3. (Columns 1 and 2 contain the
data from Exercise 18.17.) The multiple regression outputs are shown in
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Refer to Exercise 19.14. The histogram of
the residuals and the graph of the residuals and the predicted values are shown
below.

a Does it appear that the normality
requirement is violated? Explain.

b Is the error variable variance constant? Explain.

XR19-14 Suppose that the statistics
practitioner who did the analysis described in Exercise 18.21 wanted to
investigate other factors that determine height. As part of the same study, she
recorded the heights of the mothers in column 3. (Columns 1 and 2 contain the
data from Exercise 18.17.) The multiple regression outputs are shown in the
table below.

a What is the standard error of estimate?
What does this statistic tell you?

b What is the coefficient of determination?
What does this statistic tell you?

c What is the coefficient of determination,
adjusted for degrees of freedom? What do this statistic and the one referred to
in part (b) tell you about how well the model fits the data?

d Test the overall utility of the model.
What does the test result tell you?

e Interpret each of the coefficients.

f Do these data allow the statistics
practitioner to infer that the heights of the sons and the fathers are linearly
related?

g Do these data allow the statistics
practitioner to infer that the heights of the sons and the mothers are linearly
related?

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