Question

1) A researcher wants to estimate the average income of parents of high school students. He decides to survey a sample of 250 students who are visiting Harvard University. Is this a representative sample? Explain your answer.

2) According to a study, persistent poverty during the first 5 years of life leave children with IQs 7.1 lower at age 5 than children who suffer from no poverty during that period. Is this statistical study an observational study or a designed experiment? Explain your answer.

3) There are 100 students in a psychology class. You need to do a study as a project for the course and have to obtain a simple random sample of 5 out of 100 students. Use the random number table, start at the three digit number in line number 10 and column numbers 7-9.

Answer 1

1)

The researcher wants to estimate the average income of parents of high school students. So he would want a sample that would represent the entire population, that is, income of parents of all high school students.

The researcher took a sample of 250 students who are visiting Harvard University. Since education at Harvard is expensive so it might be the case that most parents are financially strong with high income. This might lead to a misrepresentation.

So, No, this isn't a representative sample.