Exam 4: Some Key Ingredients for Inferential Statistics: the Normal Curve, Sample Versus Population, and Probability

A person has a score that is in the bottom 42% of the scores. What is the highest Z score this person could have? (Assume a normal distribution.)

On a test of physical fitness, 18-year-olds' scores are normally distributed with a mean of 140 and a standard deviation of 25. a. Approximately what percentage of 18-year-olds have scores above 190? Below 165? Below 115? Use the normal curve approximation rules and be sure to include a sketch. b. Explain your answers and procedure to a person who is not familiar with the normal curve or normal curve areas.

Survey organizations in the United States today are not allowed to call ____________ , creating some bias in the poll results.

__________ selection is a procedure of selecting a sample of individuals to study such that each individual in the population has an equal chance of being selected.

Relative frequency is:

In almost any published research article, the Results section will describe the methods associated with determining statistical significance, followed by something like: "p < .05 or p < .01." (True or False)

In __________ sampling, the researcher often begins with a complete list of all the members of the population.

Today, survey sampling uses complex methods in order to ensure a close approximation to true __________ sampling.

The Gallup Poll correctly predicted George H. W. Bush's 1988 victory using only 4,089 interviews. Why, then, did the Gallup Poll in 1948 wrongly predict Dewey's victory over Truman when they used 50,000 interviews to make the prediction?

A(n)__________ shows the percentage of scores between the mean and any particular Z score.

To change a proportion into a percent: