In an article in the Journal of Marketing, Bayusstudied the differences between \"early replacement buyers” and\"late replacement buyers” in making consumer durable goodreplacement purchases. Early replacement buyers are consumers whoreplace a product during the early part of its lifetime, while latereplacement buyers make replacement purchases late in the product’slifetime. In particular, Bayus studied automobile replacementpurchases. Consumers who traded in cars with ages of zero to threeyears and mileages of no more than 35,000 miles were classified asearly replacement buyers. Consumers who traded in cars with ages ofseven or more years and mileages of more than 73,000 miles wereclassified as late replacement buyers. Bayus compared the twogroups of buyers with respect to demographic variables such asincome, education, age, and so forth. He also compared the twogroups with respect to the amount of search activity in thereplacement purchase process. Variables compared included thenumber of dealers visited, the time spent gathering information,and the time spent visiting dealers.

(a) Suppose that a random sample of 807 earlyreplacement buyers yields a mean number of dealers visited of x⎯⎯x¯= 3.3, and assume that σ equals .79. Calculate a 99percent confidence interval for the population mean number ofdealers visited by early replacement buyers. (Round youranswers to 3 decimal places.)

The 99 percent confidence interval is           [, ].

(b) Suppose that a random sample of 493 latereplacement buyers yields a mean number of dealers visited of x⎯⎯x¯= 4.2, and assume that σ equals .66. Calculate a 99percent confidence interval for the population mean number ofdealers visited by late replacement buyers. (Round youranswers to 3 decimal places.)

The 99 percent confidence interval is           [, ].

(c) Use the confidence intervals you computedin parts a and b to compare the mean number ofdealers visited by early replacement buyers with the mean number ofdealers visited by late replacement buyers. How do the meanscompare?

Mean number of dealers visited by late replacement buyersappears to be ( lower or higher?)