Chapter 1 Exercise Questions PDF

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Chapter 1 Exercise Questions...

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CH 1 HW Question 16 1.16 Glow-worms. The paper “I’m Sexy and I Glow It: Female Ornamentation in a Nocturnal Capital Breeder” is about glow-worms. Female glow-worms attract males by glowing and flying males search for females. The authors write, “We found brightness to correlate with female fecundity.” The file Glow-Worms has data on 26 female glowworms captured in Finland. The variable Lantern is the size, in mm, of the part of the female abdomen that glows. The variable Eggs is number of eggs laid by the glowworm. a. Fit the regression of Eggs on Lantern. What is the fitted regression model? Eggs = -8.98 + 7.33Lantern b. Interpret the coefficient of Lantern in the context of this setting. If the Lantern size increases by 1 mm, the eggs laid increase by 7.3 on average. c. Suppose a glow-worm has a lantern size of 14 mm. What is the predicted number of eggs she will lay? Eggs = -8.98 + 7.33 (14) = 93.64 If the glow-worm’s lantern size is 14mm, the eggs laid are 93.64.

Question 20 1.20 Houses in Grinnell, CHOOSE/FIT. The file GrinnellHouses contains data from 929 house sales in Grinnell, Iowa, between 2005 and into 2015. In this question we investigate the relationship of the list price of the home (what the seller asks for the home) to the final sale price. One would expect there to be a strong relationship. In most markets, including Grinnell during this period, list price almost always exceeds sale price. a. Make a scatterplot with ListPrice on the horizontal axis and SalePrice on the vertical axis. Comment on the pattern. There’s strong linear relationship between ListPrice and SalePrice, the plot indicates, see the screenshot below.

b. Find the least squares regression line for predicting sale price of a home based on list price of that home. Term Intercept ListPrice

Estimate -144.8329 0.9430648

Std Error 523.5836 0.003201

t Ratio -0.28 294.58

Prob > |t| 0.7821...