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Husbands and wives The mean height of American women in their early twenties is 64.5inches and the standard deviation is 2.5inches. The mean height of men the same age is 68.5inches, with a standard deviation of 2.7inches. The correlation between the heights of husbands and wives is about r = 0.5.

(a) Find the equation of the least-squares regression line for predicting the husband鈥檚 height from the wife鈥檚 height. Show your work.

(b) Use your regression line to predict the height of the husband of a woman who is 67inches tall. Explain why you could have given this result without doing the calculation

Short Answer

Expert verified

From the given information,

a)The equation of the least-squares line isY^=33.67+0.54X

b) A regression line is used to predict the response Yfor a specific value of the explanatory variable X .

Step by step solution

01

Part (a) Step 1: Given Information

It is given in the question that,

According to the table, the heights of husbands and wives are correlated as:r=0.5

02

Part (a) Step 2: Explanation

In regression analysis, the least-squares line is:

Y=a+bXwith slope Y=a+bXandYintercept a= Y--bX-

Based on the least-squares regression line plotting husband's height against wife's height, the slope is as follows:

localid="1649943536880" b=0.52.72.5=0.54

Since the least-squares line passes through(X,-Y-)we use this information to find the intercept.

localid="1649943542257" Y-=a+bX-a=68.5-0.5464.5=33.67

03

Part (b) Step 1: Given Information

It is given in the question that, The correlation between the heights of husbands and wives is about r = 0.5.

Use your regression line to predict the height of the husband of a woman who is 67inches tall.

04

Part (b) Step 2: Explanation 

Based on a woman who stands67inches tall, the height of her husband is,

localid="1650003095350" Y=33.67+0.54X=33.67+0.5467=69.85

Y=69.85inches

For a specific value of the explanatory variable localid="1649943566363" X, a regression line is used to predict the responselocalid="1649943572450" Y.

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