A biologist is studying the levels of heavy metal contaminants among a population of the South Nakaratuan Chubby Bat. The biologist is interested in constructing a simple linear regression model to investigate the relationship between weight of an animal and the level of heavy metal contamination. In the proposed regression model the level of contaminant is the response variable and weight is the explanatory variable. The contaminant level is measured in parts per billion (ppb) and weight in grams. A random sample of 20 individuals is selected and measurements are taken. Contaminant study in
South Nakaratuan Chubby Bat
Contaminant level
(ppb) Weight
(g)
138 101
224 145
166 112
201 138
210 129
167 120
161 110
217 141
197 127
166 118
213 143
202 124
213 132
189 120
178 124
236 148
193 137
160 117
163 121
247 103
a. Plotting the data, the researcher notices an obvious outlier. They decide to do the regression analysis with and without the outlier and compare the results.
b. Calculate the slope (b1) and intercept (b0) of the simple regression equation using the data provided.
c. Find the proportion of variation in the values of contaminant level that is explained by the regression model
d. Find the proportion of variation in the values of contaminant level that is explained by the regression model.