1. In order to answer a research question about a population of 17,000 students, scientists cannot interview every person in the population for practical reasons. Instead, scientists

a.only study populations with a manageable number of people.

b.ask the research question to a carefully chosen set of people from the population and use the results to learn something about this particular set of people.

c.ask the research question to a random subset of people from the population and use the results to learn something about the large population.

d.conduct surveys through the mail or online only.

2-The random variable 'length of a tulip stem' could be modeled with a

a.normal distribution.

b.binomial distribution.

c.Poisson distribution.

d.standard error of the mean.

3-Probability distributions are used to

a.select a sample.

b.distribute random variables evenly.

c.approximate the behavior of a random variable.

d.distribute probabilities evenly.

4-The standard deviation of a normal distribution tells us

a.about the spread of our data.

b.the most likely value of our data.

c.the least likely value of our data.

d.the height of our data.

5-Which of the following is not a random variable?

a.number of emergency calls in an hour

b.time taken to get to a fire

c.marital status

d.weight of a suitcase