Quiz 3 Solutions

SS 1023/2037 Quiz 3 Instructor: Johanna de Haan-Ward October 24 2023 SHORT ANSWER: 4 QUESTIONS QUESTION 1 (2 points) A consumer products company relies on direct mail marketing pieces as a major component of its advertising campaigns. The company has three different designs for a new brochure and wants to evaluate their effectiveness, as there are substantial differences in costs between the three designs. The company decides to test the three designs by mailing 5000 samples of each to potential customers in four different regions of the country. There may be regional differences in the customer base. a) What is the treatment? How many levels does it have? Brochure design, 3 levels b) What is the blocking factor? How many levels does it have? Region, 4 levels QUESTION 2 (3 points) A school district is considering changing the time school starts and ends. This school district consists of 25 elementary schools, 8 middle schools, and 5 high schools, with 16 634 students in total. They want to get the opinions of the parents/guardians of students about this potential change. They will survey the parents, but cannot survey all of them, so they will take a sample of 400 students, then survey their parents. a) Describe a simple random sampling procedure the district could use to sample 400 students, whose parents will be surveyed. Draw names at random, or assign each student a number then use a random number generator. b) Suppose instead they want to use a stratified sample. What characteristic of the schools could be used to define the strata? Type of school: Elementary, middle, high c) What is the advantage of using a stratified sample over a simple random sample? Stratified sampling assures diversity of the sample, which here means that the sample will contain elementary, middle, and high school parents.