The moisture content in bulk grain is important, because high values can encourage the development of fungi. Potential buyers want to know how much water they are buying along with their grain. Two...

The moisture content in bulk grain is important, because high values can encourage the development of fungi. Potential buyers want to know how much water they are buying along with their grain. Two direct methods for measuring the moisture content are by means of a chemical reaction (with iodine in the presence of sulfur dioxide) and by distillation. A random sample of bulk grain was obtained, and the moisture content of each grain sample was measured as a percentage of water using each method. Assuming normality, conduct the appropriate hypothesis test to determine whether there is any difference in the population mean moisture content of bulk grain measured by chemical reaction and by distillation.

Two recent studies suggest that people who drive really nice cars exhibit some very bad habits. In one study, as a car approached a crosswalk, a person stepped into the road, and the driver’s reaction was recorded. In another, similar study, independent random samples of drivers were selected, and their behavior was observed at a four-way intersection. For luxury-car drivers,
and 130 cut ahead in the usual four-way rotation. For ordinary-car drivers,
and 82 violated the four-way-intersection rotation rule. Is there any evidence to suggest that the proportion of luxury-car drivers with insufferable driving habits is greater than the proportion of ordinary-car drivers with similar habits?  Note: The largest group of driving-rule etiquette violators were men, ages 35–50, with blue BMWs.