Quiz

13) The Big Red Arcade and Pizza Palace caters to young teens and sells tokens to play arcade games for 25¢ each and slices of pizza for 50¢ each. The distribution of sales of pizza slices per customer and sales of arcade tokens per customer is below. # Slices of Pizza 0 1 2 3 4 5 Probability 0.05 0.10 0.20 0.30 0.15 0.20 # Arcade Games 0 1 2 3 4 5 Probability 0.01 0.04 0.15 0.20 0.25 0.35 If the expected number of arcade games played by the typical customer is 2 games, what is the standard deviation of the number of arcade games played per customer?

A. 1.43

B. 2.96

C. 4.43

D. 2.10

For a sample size of 1, the sampling distribution of the mean will be normally distributed

A. regardless of the shape of the population.

B. only if the population is normally distributed.

C. only if the shape of the population is positively skewed.

D. only if the population values are larger than 30.

10) Ten bolts were selected randomly from a production line and the diameter of each was measured. Why do these diameters not have a binomial distribution?

A.           They have equal probability of success.

B.           The diameters of the bolts are not independent of one another.

C.           Diameter is a continuous random variable.

D.           They do have a binomial distribution.

11) The local police department must write, on average, 5 tickets a day to keep department revenues at budgeted levels. Suppose the number of tickets written per day follows a Poisson distribution with a mean of 5.5 tickets per day. Interpret the value of the mean.

A.           The number of tickets written most often is 5.5 tickets per day

B.           Half of the days have less than 5.5 tickets written and half of the days have more than 5.5 tickets written

C.           If we sampled all days, the arithmetic average or expected number of tickets written would be 5.5 tickets per day.

D.           The mean cannot be interpreted.

12) The Information Commons in the main library has 150 personal computers. The probability that any one of them will require repair on a given day is 0.02. To find the probability that exactly 25 of the computers will require repair, one would use what type of probability distribution?

A.           Binomial distribution

B.           Poisson distribution

C.           Normal distribution

D.           Hypergeometric distribution

Which of the following statements is NOT true?

A. Estimating parameters is an important aspect of descriptive statistics.

B. Scientific progress consists of continual refinement of theories through hypothesis testing.

C. A statistical test may be significant yet have no practical importance.

D. Statistics is the science of collecting, organizing, analyzing, interpreting, and presenting data.

The expected value of the sampling distribution of the sample mean equals the population mean

A. for all populations.

B. when the population is normally distributed.

C. when the population is symmetric.

D. when the population size N > 30.

The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The 10 female students in the class averaged

A. 85

B. 75

C. 70

D. 80

When a change has occurred in the mean of the process distribution, the result is referred to as

A. a level shift.

B. instability.

C. a cycle.

D. a trend.