A survey was mailed to a total of 400 students; 100 were randomly selected from each of the freshman, sophomore, junior and senior classes last semester. What sampling method was used?
There are many different types of sampling methods. Check them out and see which one closely fits your scenario.
Let smokers =A.
Gum chewers=B
n(AuB)= n(A) + n(B) -n(AnB).
100 + 150 - 75
=250-75=175
neither =400-175=225
To determine the sampling method used in this scenario, we need to understand the different types of sampling methods. Common sampling methods include random sampling, stratified sampling, cluster sampling, and systematic sampling. Let's go through each one and determine which method was likely used in this survey:
1. Random Sampling: In random sampling, each member of the population has an equal chance of being selected. It involves randomly selecting individuals from the entire population. In this scenario, if the 100 students from each class were selected randomly without any bias or predetermined criteria, then random sampling was used.
2. Stratified Sampling: Stratified sampling is used when a population can be divided into subgroups (strata) based on certain characteristics, and then individuals are randomly selected from each subgroup. If the students were divided into four strata (freshman, sophomore, junior, and senior classes) and 100 students were randomly selected from each group, then stratified sampling was used.
3. Cluster Sampling: Cluster sampling involves dividing the population into groups or clusters, and then some or all of the clusters are randomly selected for analysis. In this scenario, if the students were grouped based on a particular characteristic (such as classes) and all four classes were randomly selected, then cluster sampling was used.
4. Systematic Sampling: Systematic sampling involves selecting every kth individual from a list or population. For example, if the list of students is alphabetically ordered, and every 4th student was selected, then systematic sampling was used.
From the information given, it appears that stratified sampling was employed. The 400 students were divided into four subgroups (freshman, sophomore, junior, and senior), and then 100 students were randomly selected from each class.