Designing a Study Assignment

Which of these methods is most likely to be biased? cluster systematic simple random stratified convenience

convenience

To find how high school students feel about hot lunches, Adam walks to the nearest high school and gives a survey postcard to every twentieth student that enters the building. He asks the students to mail the postcard in if they choose to participate in the study. Select all sampling methods used. cluster convenience simple random stratified systematic voluntary

convenience systematic voluntary

A company redesigned its website. It wants to collect data to see if it is user friendly. Which would be the best way to collect the data?

sample survey

A company wants to administer a satisfaction survey to its current customers. Using their customer database, the company randomly selects 100 customers and asks them about their level of satisfaction with the company. What type of sampling method is used?

simple random sample

To determine customer satisfaction with their service department, an automobile dealer randomly selects 20 hybrid-vehicle owners, 20 SUV owners, and 20 sedan owners and sends them a survey. What type of sampling is used? cluster convenience simple random stratified systematic

stratified

To estimate the percentage of defects in a recent manufacturing batch, a quality-control manager selects every twentieth widget that comes off the assembly line, starting with the tenth, until he obtains a sample of sixty widgets. What type of sampling method is used?

systematic

A survey of 1,565 households estimated that 72% of the households in a given state owned a television. 1. What is the population? all the households in given state 1565 households surveyed 1127 households that owned televisions 2. What is the sample? all state households 1565 households surveyed 1127 households that owned televisions

1. all the households in given state 2. 1565 households surveyed

To find how high school students feel about hot lunches, Adam walks to the nearest high school and gives a survey postcard to every twentieth student that enters the building. He asks the students to mail the postcard in if they choose to participate in the study. Why might the method used be biased? Asking every twentieth student does not accurately represent the student population. It is likely that student opinions in one particular high school do not accurately represent the opinions of all high school students. Students that take the time to complete the survey and mail it in probably feel strongly about hot lunches.

It is likely that student opinions in one particular high school do not accurately represent the opinions of all high school students. Students that take the time to complete the survey and mail it in probably feel strongly about hot lunches.

A radio station asks its listeners to call in their opinion regarding the closing of fire stations in the city. Identify the sampling method used, and explain why this sample could be biased.

Sample response: A convenience sample is used. The sample could be biased because it limits the population to listeners of that radio station at a certain time. Callers may be more likely to have a strong opinion on the issue.

Give an example of how you would create a sample from the population of the United States using cluster sampling and stratified sampling. Then, compare and contrast these two methods.

Sample response: Divide the US into groups, by state. For cluster sampling, randomly choose twenty states and use the population of those states as the sample. For stratified sampling, randomly choose 10,000 people from every state as the sample.