Question

In each of the following scenarios, determine if the data are paired.


(a) We would like to know if Intel's stock and Southwest Airlines' stock have similar rates of return. To find out, we take a random sample of 50 days, and record Intel's and Southwest's stock on those same days.

• paired
• not paired

(b) We randomly sample 50 items from Target stores and note the price for each. Then we visit Walmart and collect the price for each of those same 50 items.

• paired
• not paired

(c) A school board would like to determine whether there is a difference in average SAT scores for students at one high school versus another high school in the district. To check, they take a simple random sample of 100 students from each high school.

• paired
• not paired

Answer 1

a) In this scenario, we need to test of intel's stock and southwest Airlines' have similar rate of return.

Which can be done by using two sample independent t-test for equality of mean.

Hence, this is not paired.

b) Here, the data has been collected for the same 50 item in two cases(one from target stores and another from walmart stores).

Hence, the data is paired and we use paired-t-test.

c) Here , we are taking two samples independently from two different schools of size 100 students.

we need to test the difference in average SAT scores for students of two different schools which can be done by using two sample independent t-test for difference of mean.

Hence, the data is not paired.