1.  

For the Crabs data file at the text website, fit the logistic regression model for the probability of a satellite (y = 1) using x= weight as the sole explanatory variable. a. Report the ML prediction equation. At the mean weight value of 2.437 kg, give a linear approximation for the estimated effect of: (i) a 1-kg increase in weight. This represents a relatively large increase, so convert this to the effect of (ii) a 0.10-kg increase, (111) a standard deviation increase in weight (0.58 kg). b. Find and interpret the average marginal effect of weight per 0.10-kg increase. c. Construct the classification table using the sample proportion of y= 1 as the cut-off. Report the sensitivity and specificity. Interpret. d. Construct a ROC curve, and report and interpret the area under it.