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Software Survey. A statistical software company is planning on updating Version \(8.1\) of its software and wants to know what features are most important to users. The company's managers have the email addresses of 1100 individuals, mostly faculty at universities, for whom they have supplied free courtesy copies of Version 8.1. They email these 1100 individuals and ask them to complete a survey online. A total of 186 of these individuals complete the survey. a. What is the population of interest to the software company? Do you think the 1100 individuals contacted are representative of the population? Explain your reasons. b. What is the sample? From what group is information actually obtained?

Sampling Gravestones. The local genealogical society in Coles County, Illinois, has compiled records on all 55,914 gravestones in cemeteries in the county for the years 1825 through 1985 . Historians plan to use these records to learn about African Americans in Coles County's history. They first choose an SRS of 395 records to check their accuracy by visiting the actual gravestones. 3 a. How would you label the 55,914 records? b. Use software, the Simple Random Sample applet, or Table \(\underline{B}\) (starting at line 141 ) to choose the first six records for the SRS.

An online store contacts 1000 customers from its list of customers who have purchased in the past year. In all, 696 of the 1000 say that they are very satisfied with the store's website. The population in this setting is a. all customers who have purchased something in the past year. b. the 1000 customers contacted. c. the 696 customers who were very satisfied with the store's website.

Sampling Greenville County. The rails to trails program involves the conversion of old rail corridors into multipurpose trails for recreation and transportation. Researchers were interested in obtaining information on characteristics of users and nonusers of a 10 -mile-long paved greenway trail in Greenville, South Carolina, that connects residential areas to both a university campus and the commercial downtown area of the city. Random digit dialing of residential numbers was done using a database of exchanges. A total of 2461 persons were contacted, and 726 of them completed the survey. When a household was reached, surveyors asked to speak to the adult over 18 with the next birthday. No cell phone numbers \(\mathrm{~ w e r e ~ i n c l u d e d ~ i n ~ t h e ~ s a m p l e . ? ? ?}\) a. What is the population of interest? What is the response rate for the survey? b. The following table gives the number of adults between 18 and 64 and over 65 in both the sample and the county (only 689 of the 726 respondents to the survey provided data on their ages). The county counts were obtained from the U.S. Census Bureau: What percentage of the sample is between 18 and 64? What percentage of the population is between 18 and 64? Does this difference surprise you, given the sampling method described? Explain briefly. c. Among the 726 respondents, 181 , or \(24.9 \%\), reported having used the trail in the past six months. Do you think this sampling method gives biased information about the percentage of Greenville County adults who have used the trail in the past six months? What is the likely direction of bias? Explain briefly.