1. Describe whether the following study would most likely be "observational" or "experimental", and why it would be so. Researchers test two different blood pressure medicines to determine effectiveness.
2. Assume that you have selected 10 students enrolled at your college and have collected data for these three variables:
X: number of courses enrolled
Y: total cost of text books and supplies for courses
Z: method of payment used for textbooks and supplies
a. What is the population?
b. What is the sample?
c. Classify the three variables as nominal, ordinal, discrete or continuous.
3. What is it that differentiates a binomial probability distribution from any other probability distribution?
4. The employees at a General Motors assembly plant are polled as they leave work. Each is asked, "What brand of automobile are you riding home in?" The random variable to be reported is the number of each brand mentioned. Is x a binomial random variable? Justify your answer.
5. What are the primary advantages of the Standard Normal Distribution that other normal distributions do not have?
6. Find the standard z-score that corresponds to the following: Eighty percent of the distribution is below (to the left of) this value.
7. The histograms of some sampling distributions are symmetrical. T-F What would make a histogram symmetrical, and give an example of a symmetrical distribution?
8. A random sample of size 36 is to be selected from a population that has a mean μ = 50 and a standard deviation σ of 10.
Find the standard (z) score for a sample value of 40.
9. Describe what a type I and type II error would be for the following null hypothesis:
H_0: There is no difference between steam and chemical carpet cleaning methods.
10. Answer "True" if the statement is always true. If the statement is not always true, replace the underlined words with words that make the statement always true.
Failing to reject the null hypothesis when it is false is a correct decision.