Modern medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x of a 1-year old baby and the weight y of the mature adult (30 years old)? A random sample of medical files produced the following information for 14 females. x (lb) 19 24 25 23 20 15 25 21 17 24 26 22 18 19 y (lb) 126 126 125 124 130 120 145 130 130 130 130 140 110 115 In this setting we have Σx = 298, Σy = 1781, Σx2 = 6492, Σy2 = 227,603, and Σxy = 38,105. (a) Find x, y, b, and the equation of the least-squares line. (Round your answers for x and y to two decimal places. Round your answers for least-squares estimates to four decimal places.) x =  y =  b =  ŷ =  +  xind the sample correlation coefficient r and the coefficient of determination. (Round your answers to three decimal places.) r =   r2 =   What percentage of variation in y is explained by the least-squares model? (Round your answer to one decimal place.)  %

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.4: Distributions Of Data
Problem 19PFA
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Modern medical practice tells us not to encourage babies to become too fat. Is there a positive correlation between the weight x of a 1-year old baby and the weight y of the mature adult (30 years old)? A random sample of medical files produced the following information for 14 females.

x (lb) 19 24 25 23 20 15 25 21 17 24 26 22 18 19
y (lb) 126 126 125 124 130 120 145 130 130 130 130 140 110 115

In this setting we have Σx = 298, Σy = 1781, Σx2 = 6492, Σy2 = 227,603, and Σxy = 38,105.

(a) Find x, y, b, and the equation of the least-squares line. (Round your answers for x and y to two decimal places. Round your answers for least-squares estimates to four decimal places.)
x
y
b
ŷ +  x
ind the sample correlation coefficient r and the coefficient of determination. (Round your answers to three decimal places.)
r =  
r2 =  

What percentage of variation in y is explained by the least-squares model? (Round your answer to one decimal place.)
 %

(d) Test the claim that the population correlation coefficient ? is positive at the 1% level of significance. (Round your test statistic to three decimal places.)
t = 
If a female baby weighs 21 pounds at 1 year, what do you predict she will weigh at 30 years of age? (Round your answer to two decimal places.)
 lb

(f) Find Se. (Round your answer to two decimal places.)
Se = 

(g) Find a 95% confidence interval for weight at age 30 of a female who weighed 21 pounds at 1 year of age. (Round your answers to two decimal places.)
lower limit      lb
upper limit      lb

(h) Test the claim that the slope ? of the population least-squares line is positive at the 1% level of significance. (Round your test statistic to three decimal places.)
t = 
 

 

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