49, 34, and 48 students are selected from the Sophomore, Junior, and Senior classes with 496, 348, and 481 students respectively. Identify which type of sampling is used and why?
Stratified random sampling- you divide the population into strata then choose a random sample from each stratum and combine them into the overall sample.
The name of each contestant is written on a separate card, the cards are placed in a bag, and three names are picked from the bag. Identify which type of sampling is used and why?
Random sampling – each element in the population has an equal chance of being picked.
An education expert is researching teaching methods and wishes to interview teachers from a particular school district. She randomly selects ten schools from the district and interviews all of the teachers at the selected schools. Does this sampling plan result in a random sample? Simple random sample? Explain.
This is random sampling because she selected ten schools from a particular district and interviewed all the teachers from the selected schools. It required her to get a list of all schools and teachers in that district in order to make do a sampling.
A polling company obtains an alphabetical list of names of voters in a precinct. They select every 20th person from a list until a sample of 100 is obtained. They then call these 100 people. Does this sampling plan result in random sample? Simple random sample? Explain.
Simple random sample because every 20th person is selected until 100 have been obtained, then the company makes their calls.
The personnel manager at a company wants to investigate job satisfaction among the female employees. One evening after a meeting she talks to all 30 female employees who attended the meeting. Does this sampling plan result in a random sample? Simple random sample? Explain.
This is simple random sampling because there are a total of 30 female employees and all 30 were interviewed....