Question

question #9
a simple random sample of ten subjects from a population is one in which:
most, but not all, groups of size ten have the same chance of being selected.
any group of ten subjects has the same chance of being the selected sample.
a simple way was found to choose ten subjects at random from the population.
we record the data provided by the first ten subjects who respond to the survey.

question #10
you wish to survey people who have brought in their cars for service during the past month. you decide to pick a random sample of gas stations in the city and then survey all the customers from those who had work done during the past month.
this is an example of:
simple random sampling
convenience sampling
cluster sampling
stratified random sampling

Explanation:

Question #9

In a simple random sample, every possible group (of the specified size) from the population has an equal chance of being selected. The first option is incorrect because it says "most, but not all". The third option is too vague as it doesn't emphasize the equal - chance aspect for all groups. The fourth option is about a non - random (response - based) selection which is not simple random sampling.

• Simple Random Sampling: Would involve randomly selecting individual customers, not gas stations first.
• Convenience Sampling: Is based on ease of access (e.g., surveying customers at one easily - reachable gas station), not random selection of gas stations.
• Cluster Sampling: Here, gas stations are clusters. We randomly select some clusters (gas stations) and then survey all the elements (customers) within those selected clusters.
• Stratified Random Sampling: Would require dividing the population (customers) into strata (e.g., by car type, service type) and then sampling from each stratum.

Answer:

Any group of ten subjects has the same chance of being the selected sample.

Question #10