Q6- Listed below are the body lengths (in inches) and weights (in lb) of randomly selected bears:
Length |
40 64 65 49 47 |
Weight |
65 356 316 94 86 |
a. Find the value of the linear correlation coefficient.
b. Letting y represent weights of bears and letting x represent their lengths, find the regression equation.
c. Based on the given sample data, what is the best predicted weight of a bear with a length of 72.0 inch?
Please write the answer in details.
Ans:
Length,x | weight,y | xy | x^2 | y^2 | |
1 | 40 | 65 | 2600 | 1600 | 4225 |
2 | 64 | 356 | 22784 | 4096 | 126736 |
3 | 65 | 316 | 20540 | 4225 | 99856 |
4 | 49 | 94 | 4606 | 2401 | 8836 |
5 | 47 | 86 | 4042 | 2209 | 7396 |
Total | 265 | 917 | 54572 | 14531 | 247049 |
a) linear correlation coefficient,r=(5*54572-265*917)/SQRT((5*14531-265^2)*(5*247049-917^2))=0.964
b)
slope,b=(5*54572-265*917)/(5*14531-265^2)=12.286
y-intercept,a=(917-12.286*265)/5=-467.76
y'=12.286x-467.76
predicted weight=12.286*length-467.76
c)
when x=72
predicted weight=12.286*72-467.76=416.83
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