For each sampling scheme listed below, (i) identify the population of interest,
ID: 2924100 • Letter: F
Question
For each sampling scheme listed below, (i) identify the population of interest, (ii) identify the sample, and (iii) give a reason that the sample may not be representative of the population.
a) Mary wants to say something about ALL students at the University of Iowa. Mary goes to the main library at 8am on a Saturday morning and observes every 5th person that walks in the door to see if they are wearing Hawkeye apparel until she has a sample of 30 people.
b) Eric wants to make a conclusion regarding the proportion of green M&M’s. He goes to three stores in Iowa City and purchases a 19.2 oz bag at each store. Then he computes the proportion of green M&M’s that he bought.
c) Subash sits at his dorm window for an hour one night and watches cars drive by. He records whether each car is red or not.
d) Jia is a cashier at a grocery store and is interested in the proportion of customers that purchase milk. During October, she works four different Monday 7am-10am shifts and records whether each customer coming through her lane purchases milk or not.
Explanation / Answer
a)
i) Mary wants to say something about ALL students at the University of Iowa. So, the population of interest are students at the University of Iowa who are wearing Hawkeye apparel.
ii) The sample is every 5th person that walks in the library door after 8 am on a saturday morning and the sample size is 30.
iii) The sample may not be representative of the population as the sample was not a random sample and also was not carried for other days and at other areas of the college. So, the sample may not represent the population.
b)
i) Eric wants to make a conclusion regarding the proportion of green M&M’s. So, the population of interest are green M&M’s.
ii) The sample is 3 19.2 oz bags of M&M's purchased at three stores in Iowa City.
iii) The sample may not be representative of the population as the sample size is very low and also was not carried at other cities. So, the sample may not represent the population.
c)
i) Subhash records whether each car is red or not. So, the population of interest are red cars.
ii) The sample are red cars passed by dorm window for an hour one night.
iii) The sample may not be representative of the population as the sample was not random and and was carried only for one night. That night may be a weekend and have fewer cars on the roads. So, the sample may not represent the population.
d)
i) Jia is interested in the proportion of customers that purchase milk. So, the population of interest are customers that purchase milk.
ii) The sample are all customers who purchases from a grocery store through Jia's lane on all October Monday's between 7am-10am.
iii) The sample may not be representative of the population as the sample was not random and and was carried only for one weekday/month and fix timeperiod. The proportion of customers that purchase milk between 7am-10am may be higher than other time periods. So, the sample may not represent the population.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.