Exam 5: Probability, Normal Distributions, and Z Scores

Suppose that the probability that any child of alcoholic parents becomes alcoholic is p = .16.Assuming independent outcomes,the probability that two children of alcoholic parents will be alcoholic equals

Below is the probability distribution for random variable x.Which of the following is most probable?

Below is the probability distribution for random variable x.What is the standard deviation of this probability distribution?

For mutually exclusive outcomes,one or the other outcome can occur (Outcome A or Outcome B),but not both outcomes (Outcome A and Outcome B)

The probability of a college student being employed is p = .35.The probability of a student being employed and dropping out of college is p = .20.Hence,the probability of a student dropping out of college,given that he or she is employed,is

A researcher determines that the probability of missing class among students at a local school is p = .16.Assuming that the school has 300 students enrolled,how many students can we expect to miss class on a given day? Hint: This is a binomial probability distribution.

If the variance of a probability distribution is 121,then the standard deviation is

A researcher determines that the relative frequency of participants with prescription glasses is .23.Hence,the probability that participants will wear prescription glasses must be greater than p = .23.

A researcher records the number of mistakes made during a memory skills task.He finds that the probability that participants in this study made 0 mistakes is p = .22;made 1 mistake is p = .30;made 2 mistakes is p = .16;made 3 mistakes is p = .12;and made 4 or more mistakes is p = .25.Is this probability distribution accurate?

Which rule states that when two outcomes are independent,the probability that these outcomes occur together is the product of their individual probabilities?

The expected value of a random variable is the mean of a probability distribution.

If the standard deviation of a probability distribution is 9,then the variance is

Conditional outcomes refer to those where the probability of one outcome is independent of the probability of the occurrence of the second outcome.

When the probability of one outcome changes depending on the occurrence of a second outcome,these outcomes are referred to as

Which of the following is NOT a characteristic of probability?

A news poll showed that voters had no preference for either of three candidates.In this example,the probability of a vote for,say,Candidate A equals

By definition,the probability of an outcome or event is

A researcher records the number of buckets of popcorn purchased by patrons during one night at the movies.She finds that the probability that a patron purchased 0 buckets of popcorn is p = .27;1 bucket is p = .51;2 buckets is p = .17;and 3 buckets is p = .05.How many buckets of popcorn can we expect a patron to purchase per night at the movies in the long run?

A researcher reports that the probability of a college student living on campus is p = .38.If a small local college has 2,000 students enrolled,then what is the standard deviation of college students living on campus? Hint: This is a binomial probability distribution.

A professor records the grades for his class of students.He finds that the probability that a student earns an A is p = .14;earns a B is p = .36;earns a C is p = .32;earns a D is p = .10;and earns an F is p = .08.What is the probability that a student earns a B or better in this class?