Question

Determine which inference procedures we studied in Chapters 20-23 are appropriate for an- alyzing the following situations, and justify your answer (for example, ‘I’d use a two sample confidence interval for comparison of means because...’). You don’t need to carry out any of the procedures.

(a) How seriously do people view speeding in comparison with other annoying behaviors? A large random sample of adults was asked to rate a number of behaviors on a scale of 1 (no problem at all) to 5 (a very severe problem). Do speeding drivers get a higher average rating than noisy neighbors?

(b) you have data on rainwater collected at 16 locations in the Adirondack Mountains of New York State. One measurement is the acidity of the water, measured by pH on a scale of 0 to 14 (the pH of distilled water is 7.0). Estimate the average acidity of rainwater in that region.

(c) Downing in bathtubs is a major cause of death in children less than five years old. A random sample of parents was asked many questions related to bathtub safety. Overall 85% of the sample said they used baby bathtubs for infants. Estimate the percent of all parents of young children who use baby bathtubs.

Answer 1

A. Can be done using hypothesis testing. Take the mean and standard deviation of scores in both the cases. Compare the averages using a paired-t test. If the test is significant, we can conclude that speeding drivers have a higher average rating.

B. This will be done by sample mean. We have acidity levels of 16 locations, and we need to find the average acidity in the region. So, we take the sample mean of acidity in those 16 locations.

C. creating a confidence interval, let's say of 95% confidence interval. Since we are restricted to a sample, our best estimate would be a spread of proportion of parents at a particular confidence interval.