Exam 1 lesson 2
A internet site asks its members to call in their opinion regarding their reluctance to provide credit
Convenience sampling
For a poll of voters regarding a referendum calling for a national value-added tax, design a sampling method to obtain the inviduals in the sample. Be sure to support your choice. Which sampling method would most likely be used in a poll of voters regarding a referendum calling for a national value-added tax?
Use stratified random sampling. Since this is a national issue, different geographical locations are likely to have similar views
Determine whether the following statement is true or false. Explain. When conducting a cluster sample, it is better to have fewer clusters with more individuals when the clusters are heterogeneous.
True, because when the clusters are heterogeneous, they are scaled down versions of the population.
Determine whether the following statement is true or false. Explain. A simple random sample is always preferred because it obtains the same information as other sampling plans but requires a smaller sample size.
False, because other sampling techniques may provide more information for less cost than a simple random sample.
Determine whether the following statement is true or false. Explain. Inferences based on voluntary response samples are generally not reliable.
True, because it is often the case that the individuals who volunteer do not accurately represent the population.
As part of a college literature course, students must select three classic works of literature from the provided list and complete critical book reviews for each selected work. Write a short description of the processes that can be used to generate a simple random sample of threebooks. Obtain a simple random sample of size 3 from this list. 1) which of the following would produce a simple random sample? select all that apply
(1) list each book on a separate piece of paper, place them in a hat, and pick three. and Number the books from 1 to 9 and use a random number table to produce 3 different one digit numbers corresponding to the books selected.
Which sampling method does not require a Frame?
Systematic
A ________ is obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups.
Cluster sample
To determine Customer opinion of their check in service, American Airlines randomly selects 40 flights during a certain week and survey's all passengers on the flights
Cluster sampling
Determine whether the following statement is true or false. Explain. When taking a systematic random sample of size n, every group of size n from the population has the same chance of being selected.
False, because certain groups would never be selected.
Determine whether the following statement is true or false. Explain. When obtaining a stratified sample, the number of individuals included within each stratum must be equal.
False. Within stratified samples, the number of individuals sampled from each stratum should be proportional to the size of the strata in the population.
A pharmaceutical company wants to conduct a survey of 30 individuals who have high cholesterol. The company has obtained a list from primary care physicians throughout the country of 5400 individuals who are known to have high cholesterol. Design a sampling method to obtain the individuals in the sample. Be sure to support the choice.
Group the individuals by common primary care physician. Assign each physician a different number and use a random number table to select physicians until the total number of patients of all the selected physicians is at least 30. Your answer is correct. C. Alphabetize the list of 5400 individuals by last name and select one of the first 180 individuals at random. Starting from the selected individual, read down the list and select every 180th individual. Your answer is correct. D. Group the individuals by common primary care physician. For each group, assign all the individuals different numbers, and use a random number table to select an appropriate number of individuals.
what does it mean when sampling is done without replacement?
Once an individual is selected, the individual cannot be selected again.
what is K?
Population N/sample N
Nissan wants to administer a satisfaction survey to its current customers. Using their customerdatabase, the company randomly selects 70 customers and asks them about their level of satisfaction with the company.
Simple random sample
What is a frame?
a frame is a list of the individuals in the population being studied
Define simple random sampling
a sample size of n from a population of size N is obtained through simple random sampling if every possible sample of size n has an equally likely chance of occurring. The sample is then called a simple random sample
To determine customer opinion of their safety features, Toyota randomly selects 90 dealerships during a certain week and surveys all customers visiting the dealerships.
cluster sampling
General Motors wants to administer a satisfaction survey to its current customers. Using their customerdatabase, the company randomly selects 80 customers and asks them about their level of satisfaction with the company.
simple random sample
To determine her water pressure, Carolyndivides up her day into three parts: morning, afternoon, and evening. She then measures her water pressure at 3 randomly selected times during each part of the day
stratified
A __________ is obtained by dividing the population into homogeneous groups and randomly selecting individuals from each group.
stratified sample
To estimate the percentage of defects in a recent manufacturing batch, a quality control manager at IBMselects every 16th computerthat comes off the assembly line starting with the thirduntil she obtains a sample of 150 computers.
systematic
