In Exercises 9–20, identify which of these types of sampling i...

Question

In Exercises 9–20, identify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.

Highway Strength The New York State Department of Transportation evaluated the quality of the New York State Thruway by testing core samples collected at regular intervals of 1 mile.

Accepted Answer

All right, hello, everyone. So this question is asking us to identify which type of sampling is used. Random, systematic, convenience, stratified, or clustered. In a study assessing the soil quality of farmland, researchers collected soil samples at regular intervals of 500 m along designated survey routes. And here we have 5 different answer choices labeled A through E, with each one being a type of sampling method used or discussed at the beginning of the question step. So first, let's talk about the differences between each type of sampling method. Starting off with random sampling for option A. Now, random sampling means that all members of a given population have an equal chance of being selected for the survey. On the other hand, systematic sampling that's option B. Involves selecting participants for the survey. Using regular spacing or regular intervals. An example of this would be selecting every nth subject for a given survey. On the other hand, we have convenience sampling. Which is more so about ease of access to participants. And what I mean by that is that in convenience sampling, subjects are selected for the survey based on who is easiest to reach without randomization. Last but not least though, we have stratified sampling and cluster sampling, options D and E respectively. Now, I think both of these can be pretty commonly confused with each other and for good reason. So let's talk about them together. Now, what stratified and cluster sampling have in common is that both of these involve dividing a population into subgroups first. So in stratified sampling, those subgroups are called strata. And in cluster sampling, those subgroups are called clusters. But what happens after the subgroups are made is what distinguishes stratified sampling from cluster sampling. So in stratified sampling. After the subgroups have been made from the greater population. Random samples. Random samples are taken from each subgroup. So members from each subgroup are randomly selected for the survey or the study in general. Now, on the other hand, in cluster sampling, once the population has been divided into clusters. Entire clusters are instead randomly selected for the study. So now let's go back to the question at hand or the scenario. In this particular case, the researchers are collecting soil samples along regular intervals. And along designated routes. So therefore, right, the researchers are using predetermined regular intervals to collect their samples, meaning that systematic sampling is represented here. And so our answer is option B in the multiple choice. And there you have it. So with that being said, thank you so very much for watching and I hope you found this helpful.

Key Concepts

Sampling Methods

Systematic Sampling

Core Sampling

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