Stats Chapter 5

2 ways to find probability distribution

1. table 2. formula

binomial experiment

2 name distribution

Which of the following is a continuous random variable? a. The number of houses for sale in a city b. The heights of children in a preschool c. The number of correct answers on a multiple choice test d. The number of goals scored in a hockey game

b

A production process produces 2% defective parts. A sample of nine parts from the production process is selected. What is the probability that the sample contains exactly two defective parts? a. .0200 b. .9875 c. .0125 d. .9994

c binomial excel

The use of the relative frequency method to develop discrete probability distributions leads to what is called an ________ _______ _______

empirical discrete distribution

discrete random variabe

may assume either a finite number of values or an infinite sequence of values

probability distribution

describes how probabilities are distributed over the values of the random variables

continuous random variable

assume and numerical value in an interval or collection of interval

empirical discrete distribution

using a table

A continuous random variable may assume: a. only the positive integer values in an interval. b. any value in an interval or collection of intervals. c. only fractional values in an interval or collection of intervals. d. only integer values in an interval or collection of intervals.

b

A pediatrician records the heights and ages of her patients over a one month period. The average height is recorded for each age and is an example of a: a. discrete random variable. b. continuous random variable. c. complex random variable. d. none of these choices.

b

Of the passengers on a 757 airliner, 40% are female. A random sample of 25 passengers is selected. What is the expected number of female passengers in the sample? a. 6 b. 10 c. 40 d. 25

b

A binomial experiment is conducted in which 30 dishwashers are randomly selected from a production plant and tested to determine whether or not they function properly. Any specific dishwasher will work properly with a probability of p =.98. What is the random variable in this experiment? a. One dishwasher and whether it works properly b. The 30 dishwashers c. The number of dishwashers that work properly from the 30 selected d. The probability that the dishwasher works properly

c

If a random variable can assume one of five outcomes and the distribution is uniform, what is the probability function for this random variable? a. f(x)=x5 b. f(x)=5 c. f(x)=.20 d. f(x)=1/5x

c

Suppose a binomial random variable consists of 9 trials with a success of probability of .4. What are the mean and standard deviation for this binomial random variable? a. The mean is 2 and the standard deviation is 2.16. b. The mean is .4 and the standard deviation is 1. c. The mean is 3.6 and the standard deviation is 1.47. d. The mean and standard deviation cannot be calculated from the information given.

c

Twelve percent of the customers of a bank overdraw their accounts at least once a month. A sample of eight customers is selected. What is the probability that exactly two customers in the sample will overdraw their account this month? a. 0 b. .28 c. .187 d. .939

c

Which of the following could represent a discrete uniform probability function? a. f(x)=5 n where n is the number of values the random variable can assume b. f(x)=4x c. f(x)=6/5 d. f(x)=1/6

d

expected value

mean, or random variable is a measure of its central location

random variable

numerical descripton of the outcome of an experiment

The probability distribution is defined by a _______ _______, denoted by f(x), that provides the probability for each value of the random variable

probability function

We can describe a discrete probability distribution with a ____,_____,_____

table, graph, formula

The amount of time a patient must wait to be seen at a doctor's office is an example of: a. a continuous random variable. b. either a continuous or a discrete random variable, depending on the type of doctor's office. c. a discrete random variable. d. either a continuous or a discrete random variable, depending on the gender of the individual.

a

The variance is a weighted average of the: a. squared deviations from the mean. b. square root of the deviations from the median. c. square root of the deviations from the mean. d. squared deviations from the median.

a

Which of the following is not a required condition for a discrete probability function? a. Σf(x)=0 b. Σf(x)=1 c. Σf(x)≥ 0 for all values of x d. All of these choices are correct.

a