BU 305: Test 2
For the standard normal probability distribution, the area to the left of the mean is
0.5
If P(A) = 0.38, P(B) = 0.83, and P(A ∩ B) = 0.57; then P(A ∪ B) =
0.64
If A and B are mutually exclusive, then
a. P(A I B) = 0
An experiment consists of four outcomes with P(E1) = 0.2, P(E2) = 0.3, and P(E3) = 0.4. The probability of outcome E4 is
b. 0.100
If P(A) = 0.62, P(B) = 0.47, and P(A ∪ B) = 0.88; then P(A ∩ B) =
b. 0.2100
If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P(A ∪ B) =
b. 0.8
Z is a standard normal random variable. The P(1.41 < z < 2.85) equals
b. None of the alternative answers is correct.
Variance is
b. a measure of the dispersion of a random variable
A random variable that can assume only a finite number of values is referred to as a(n)
b. discrete random variable
A weighted average of the value of a random variable, where the probability function provides weights is known as
b. the expected value
The probability of at least one head in two flips of a coin is
c. 0.75
If P(A) = 0.50, P(B) = 0.60, and P(A ∩ B) = 0.30; then events A and B are
c. independent events
The probability of the intersection of two mutually exclusive events
c. must always be equal to 0
A description of how the probabilities are distributed over the values the random variable can assume is called a
c. probability distribution
For a standard normal distribution, a negative value of z indicates
c. the z is to the left of the mean
Which of the following is not a characteristic of the normal probability distribution?
d. The standard deviation must be 1
A standard normal distribution is a normal distribution with
d. a mean of 0 and a standard deviation of 1
A continuous random variable may assume
d. any value in an interval or collection of intervals
In an experiment, events A and B are mutually exclusive. If P(A) = 0.6, then the probability of B
d. cannot be larger than 0.4
Events that have no sample points in common are
d. mutually exclusive events
