On Saturdays,cars arrive at David Zebda's Scrub and Shine Car Wash at the rate of 80 cars per hour during the ten-hour shift. David wants a sample of 40 Saturday customers to answer the long version of his quality service questionnaire. He randomly selects 9 as a starting point and instructs the crew to select the 9th customer and each customer at intervals of 20 (9,29,49,etc.). His sample is a __________.
A) convenience sample
B) simple random sample
C) unsystematic sample
D) stratified sample
E) systematic sample

Question

Quizplus · Accepted Answer

The sample is a systematic sample because the customers are selected at fixed intervals (every 20th customer) from a starting point (the 9th customer). It is not a convenience sample because the customers are not simply selected based on their availability or willingness to participate. It is also not a simple random sample because the customers are not chosen completely at random without any specific method.

On Saturdays,cars Arrive at David Zebda's Scrub and Shine Car