Question

(1 point) a sample of 300 dentists from seattle is taken to estimate the median income of all seattle residents.
is this study
a. representative?
b. non - representative?
a simple random sample of 2000 men over age 18 is taken to estimate the mean weight of all adult males.
is this study
a. representative?
b. non - representative?
a simple random sample of 10 men over the age 18 is taken to estimate the mean height of all adult males.
is this study
a. representative?
b. non - representative?
a telephone survey of 1000 registered voters is conducted during the day in order to determine the chances of a certain candidate winning an election.
is this study
a. representative?
b. non - representative?
a simple random sample of 400 u.s. citizens is taken in order to estimate the mean cholesterol level of u.s. citizens.
is this study
a. representative?
b. non - representative?

Explanation:

First Question:

The sample consists of only dentists from Seattle, while the population is all Seattle residents. Dentists are a specific profession and not representative of all residents (e.g., different income distributions for other professions, non - working residents, etc.). So the study is non - representative.

A simple random sample of 2000 men over age 18 is taken to estimate the mean weight of all adult males. Since it is a simple random sample of the target population (adult males, as men over 18 are adult males), it should be representative of the population for estimating the mean weight.

A sample of only 10 men over age 18 is taken to estimate the mean height of all adult males. A sample size of 10 is very small relative to the population of all adult males. It is unlikely to capture the full range of heights in the population and will have a large sampling error, so it is non - representative.

Answer:

B. NON - REPRESENTATIVE?

Second Question: