Data Final

If A and B are any two events with P(A) = .8 and P(B|A) = .4, then the joint probability of A and B is: a. .32 b. .80 c. .40 d. 1.20

.32

If A and B are mutually exclusive events with P(A) = 0.30 and P(B) = 0.40, then the probability that either A or B occur is: a. 0.10 b. 0.12 c. 0.70 d. None of these choices are correct.

.7

If events A and B are mutually exclusive, then the probability of both events occurring simultaneously is equal to: a. any value between 0.5 and 1.0 b. 0.0 c. 1.0 d. 0.

0

The probability of an event and the probability of its complement always sum to: a. any value between 0 and 1 b. any positive value c. 1 d. 0

1

According to the empirical rule, how many observations lie within +/- 1 standard deviation from the mean? a. 50% b. 68% c. 95% d. almost all

68%

If we plot a continuous probability distribution f(x), the total probability under the curve is: a. 1 b. -1 c. 100 d. 0 Hide Feedback

a. 1

Suppose a study claims that the results are significant at the 1% significance level. Which of the following does this not imply? a. The observed results would be very unlikely if the alternative hypothesis were true. b. The p-value is less than 0.01. c. The researcher can be confident in claiming that the alternative hypothesis is true. d. The observed results would be very unlikely if the null hypothesis were true.

a. The observed results would be very unlikely if the alternative hypothesis were true.

Suppose A and B are mutually exclusive events where P(A) = 0.2 and P(B) = 0.5, then P(A or B) = 0.70. a. True b. False

a. True

Two or more events are said to be exhaustive if one of them must occur. a. True b. False

a. True

The mean μ of a probability distribution is a measure of: a. central location b. variability of the distribution c. relative likelihood d. skewness of the distribution

a. central location

One reason for standardizing random variables is to measure variables with: a. different means and standard deviations on a single scale b. similar means and standard deviations on two scales c. dissimilar means and standard deviations in like terms d. different means and standard deviations on a non-standard scale Hide Feedback

a. different means and standard deviations on a single scale

There are two types of random variables, they are: a. discrete and continuous b. exhaustive and mutually exclusive c. complementary and cumulative d. real and unreal

a. discrete and continuous

If P(A) = P(A|B), then events A and B are said to be: a. independent b. complementary c. mutually exclusive d. exhaustive

a. independent

If A and B are independent events with P(A) = 0.40 and P(B) = 0.50, then P(A/B) is 0.50. a. True b. False

b. False

Which of the following statements is true? a. Probabilities must be greater than 1. b. The sum of all probabilities for a random variable must be equal to 1. c. The sum of all probabilities for a random variable must be equal to 0. d. Probabilities must be negative.

b. The sum of all probabilities for a random variable must be equal to 1.

P(Ā) = 1 - P(A) is the: a. rule of opposites b. rule of complements c. addition rule d. commutative rule

b. rule of complements

If the value of the standard normal random variable Z is positive, then the original score is where in relationship to the mean? a. equal to the mean b. to the right of the mean c. to the left of the mean d. None of these choices are correct.

b. to the right of the mean

The standard deviation σ of a probability distribution is a measure of: a. relative likelihood b. variability of the distribution c. central location d. skewness of the distribution

b. variability of the distribution

If two events are collectively exhaustive, what is the probability that one or the other occurs? a. 0.25 b. 0.50 c. 1.00 d. This cannot be determined from the information given.

c. 1.00

Which of the following statements is least accurate? a. If the p-value is close to 1, there is virtually no evidence in support of the alternative hypothesis. b. A statistically significant result is evidence that the null hypothesis is false. c. The p-value is the probability that the alternative hypothesis is true. d. A test statistic not in the rejection region indicates a lack of support for the alternative hypothesis

c. The p-value is the probability that the alternative hypothesis is true.

Which equation shows the process of standardizing? a. f(x) = 1 - (σ/μ) b. E(X) = np c. Z = (X - μ)/σ d. E(Y) = μ

c. Z = (X - μ)/σ

A continuous probability distribution is characterized by: a. counts b. an array of individual values c. a continuum of possible values d. a list of possible value

c. a continuum of possible values

A function that associates a numerical value with each possible outcome of an uncertain event is called a: a. conditional variable b. sample variable c. random variable d. population variable

c. random variable

The standard normal distribution has a mean and a standard deviation respectively equal to: a. 1 and 1 b. 0 and 0 c. 1 and 0 d. 0 and 1

d. 0 and 1

The normal distribution is a: a. discrete distribution with two parameters b. density function of a discrete random variable c. binomial distribution with only one parameter d. continuous distribution with two parameters

d. continuous distribution with two parameters

Let A and B be the events of the FDA approving and rejecting a new drug to treat hypertension, respectively. The events A and B are: a. conditional b. independent c. unilateral d. mutually exclusive

d. mutually exclusive

Conditional probability is the probability that an event will occur, with no other events taken into consideration. a. True b. False

false

If A and B are two independent events with P(A) = 0.20 and P(B) = 0.60, then P(A and B) = 0.80. a. True b. False

false

If events A and B have nonzero probabilities, then they can be both independent and mutually exclusive. a. True b.false

false

The number of cars produced by GM during a given quarter is a continuous random variable. a. True b. False

false

The higher the value of the density function f(x), _____. a. the more likely the value x b. the less likely the value x c. the less likely the distribution is normal d. None of these choices are likely.

the more likely the value x

The temperature of the room in which you are writing this test is a continuous random variable. a. True b. False

true

The time students spend in a computer lab during one day is an example of a continuous random variable. a. True b. False

true

The total area under the normal distribution curve is equal to one. a. True b. False

true