In this setting we have Σx = 129, Σy = 82, Σx2 = 2405, Σy2 = 956, and Σxy = 1497. (a) Find x, y, b, and the equation of the least-squares line. (Round your x and y to two decimal places. Round your least-squares estimates to four decimal places.) x = y = b = ŷ = + x (c) Find the sample correlation coefficient r and the coefficient of determination. (Round your answers
Each box of Healthy Crunch breakfast cereal contains a coupon entitling you to a free package of garden seeds. At the Healthy Crunch home office, they use the weight of incoming mail to determine how many of their employees are to be assigned to collecting coupons and mailing out seed packages on a given day. (Healthy Crunch has a policy of answering all its mail on the day it is received.) Let x = weight of incoming mail and y = number of employees required to process the mail in one working day. A random sample of 8 days gave the following data.
| x (lb) | 9 | 21 | 15 | 6 | 12 | 18 | 23 | 25 |
| y (Number of employees) | 5 | 10 | 11 | 5 | 8 | 14 | 13 | 16 |
In this setting we have Σx = 129, Σy = 82, Σx2 = 2405, Σy2 = 956, and Σxy = 1497.
| x | = | |
| y | = | |
| b | = | |
| ŷ | = | + x |
(c) Find the sample
| 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.)
employees
(f) Find Se. (Round your answer to three decimal places.)
Se =
(g) Find a 95% for the number of employees required to process mail for 16 pounds of mail. (Round your answer to two decimal places.)
| lower limit | employees |
| upper limit | employees |
(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.)
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