will someone just double check my answers, please.
Identify which types of sampling is used:random,stratified, systematic,convenience.
1. a sample consists of every 20th student who leaves the bookstore.
answer:systematic
2. a pollster uses a computer to generate 500 random numbers, then interviews the voters corrosponding to those numbers.
Answer:stratified
Number 2 doesn't look like stratified to me: there's no stratification involved. Stratification is the process of grouping members of the population into relatively homogeneous subgroups before sampling, whereas here the pollster is simply picking voters at random, with each voter presumably ("presumably" because we don't know anything about the random number generator he's using) having an equal chance of being picked. That's simple random sampling.
To determine which types of sampling are used in each scenario, let's go through the steps:
1. Scenario 1: "A sample consists of every 20th student who leaves the bookstore."
In this case, students are selected systematically based on a fixed interval (every 20th student). Therefore, the sampling method used is systematic.
2. Scenario 2: "A pollster uses a computer to generate 500 random numbers, then interviews the voters corresponding to those numbers."
In this case, the voters are selected randomly using a computer-generated list of random numbers. The random selection ensures that each voter has an equal chance of being included in the sample. Therefore, the sampling method used is random.
So, to sum up:
1. Scenario 1: Systematic Sampling
2. Scenario 2: Random Sampling