Suppose that 10% of all steel shafts produced by a certain process are nonconforming but can be reworked (rather than having to be scrapped). Consider a random sample of 200 shafts, and let X denote the number among these that are nonconforming and can be reworked. What is the (approximate) probability that X is a. At most 30? b. Less than 30? c. Between 15 and 25 (inclusive)?

Chapter 17 Multiple Regression Example: In the regression example from Chapter 15 notes we tried to predict the response variable weekly fuel consumption (FUEL) on the basis of predictor variable ‘average hourly temperature’ (TEMP) during the week. We saw a tendency for the FUEL to decrease in a straight-line fashion as the temperatures increase. Fuel consumption units are in Mcf (millions of cubic feet). Now consider predicting FUEL on the basis of TEMP and a second predictor variable --- the chill factor (CHILL). The chill index is expressed as a whole number between 0 and 30. A weekly chill index near 0 indicates that, given the average hourly temperature during the week, all other major weather-related factors will only slightly increase weekly fuel consumption. A weekly chi