An online retailer needs to manage the amount of time needed to select the ordered items and assemble them for shipping. In order to assess the amount of time his assemblers devote to this task, the retailer takes a random sample of 100 orders and records the number of items in each order (Noltems) and the time needed to assemble the shipment.

a. Plot the data on a scatterplot.
b. Fit a least- squares line to the data, and comment on the degree of fit to the data.
c. Fit a regression model with the square root of Noltems as the explanatory ­variable.
d. Which model produced a better fit to the data?
e. Predict the amount of time needed to assemble a package containing 13 items using both models. Was there much difference in your predictions?

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Noltems 11 Time 1 2 2 22 2 33 3 3 4.8 14.7 13.7 9.5 24 118 10.5 12.0 14.3 16.4 17.9 145 16.7 20.1 168 Noltems 3 3 3 3 3 44 44 4 45 Time 208 26.8 12.9 130 15.4 108 20.3 22.3 20.0 219 20.7 20.9 19.9 17.1 19.1 Noltems 5 5 55 6 666 66 6 77 7 7 Time 17.2 181 17.9 129 19.6 27.9 22.2 23.2 17.5 15.3 21.8 17.9 20 18.9 29.3 Noltems 7 88 88 889999 90 10 10 Time 21.5 26.5 28.2 251 26.1 28.2 22.3 21.8 25.5 244 18.1 26.7 24.6 30.1 215 Time 25.2 28.2 22.6 313 27.2 28.8 29.7 34.3 279 29.7 28.7 34.6 380 28.0 37.0 Noltems 17 18 18 18 19 20 21 22 23 24 25 25 25 26 27 Time 32.5 39.5 39.0 37.0 35.5 38.3 44.0 39.6 42.3 34.6 44.9 474 49.2 45.8 44.0 Noltems 27 30 30 31 37 39 40 45 46 Time46.1 42.9 48.3 46.0 48.2 54.7 49.9 55.4 57.1 52.4