QBA HW
For a standard normal distribution, the probability of z ≤ 0 is _____.
.5
For the standard normal probability distribution, the area to the left of the mean is _____.
.5
The assembly time for a product is uniformly distributed between 6 and 10 minutes. The probability of assembling the product in less than 6 minutes is _____.
0
x is a random variable with the probability function: f(x) = x/6 for x = 1, 2, or 3. The expected value of x is _____.
2.333
The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. The expected number of days Pete will catch fish is _____.
2.4
When using Excel's POISSON.DIST function, one should choose TRUE for the third input if _____.
a cumulative probability is desired
The weight of an object, measured to the nearest gram, is an example of _____.
a discrete random variable
A standard normal distribution is a normal distribution with _____.
a mean of 0 and a standard deviation of 1
Variance is _____.
a measure of the dispersion of a random variable
A measure of the average value of a random variable is called a(n) _____.
c. expected value
The highest point of a normal curve occurs at _____.
the mean
The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. What is the random variable in this experiment?
the number of days out of 3 that Pete catches fish
Check My Work For a standard normal distribution, a negative value of z indicates _____.
the z is left of the mean
The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. The probability that Pete will catch fish on exactly 1 day is _____.
.096
The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. The variance of the number of days Pete will catch fish is _____.
.48
Assume z is a standard normal random variable. Then P(z ≥ 2.11) equals _____.
.0174
The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample exactly two are female?
.0413
The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample at least 6 are male?
.0499
The ages of students at a university are normally distributed with a mean of 21. What percentage of the student body is at least 21 years old?
50%
The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3. The probability there are 8 occurrences in 10 minutes is _____.
.0771
The weight of items produced by a machine is normally distributed with a mean of 8 ounces and a standard deviation of 2 ounces. Refer to Exhibit 6-5. What percentage of items will weigh between 6.4 and 8.9 ounces?
.4617
Forty percent of all registered voters in a national election are female. A random sample of 5 voters is selected. The probability that there are no females in the sample is _____.
.0778
Assume z is a standard normal random variable. Then P(1.20 ≤ z ≤ 1.85) equals _____.
.0829
The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3. The probability there are less than 3 occurrences is _____.
.1016
The probability Pete will catch fish when he goes fishing is .8. Pete is going fishing 3 days next week. The probability that Pete will catch fish on 1 or fewer days is _____.
.104
The student body of a large university consists of 60% female students. A random sample of 8 students is selected. What is the probability that among the students in the sample at least 7 are female?
.1064
Consider the continuous random variable x, which has a uniform distribution over the interval from 20 to 28. Refer to Exhibit 6-1. The probability density function has what value in the interval between 20 and 28?
.125
Consider the continuous random variable x, which has a uniform distribution over the interval from 20 to 28. Refer to Exhibit 6-1. The probability that x will take on a value of at least 26 is _____.
.250
Forty percent of all registered voters in a national election are female. A random sample of 5 voters is selected. The probability that the sample contains 2 female voters is _____.
.3456
A continuous random variable is uniformly distributed between a and b. The probability density function between a and b is _____.
1/(b-a)
The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3. The expected value of the random variable x is _____.
5.3
The random variable x is the number of occurrences of an event over an interval of 10 minutes. It can be assumed the probability of an occurrence is the same in any two time periods of an equal length. It is known that the mean number of occurrences in 10 minutes is 5.3. The random variable x satisfies which of the following probability distributions?
Poisson
Excel's _____ function can be used to compute the expected value of a discrete random variable.
SUMPRODUCT
The travel time for a college student traveling between her home and her college is uniformly distributed between 40 and 90 minutes. Refer to Exhibit 6-2. What is the random variable in this experiment?
Travel time
The Poisson probability distribution is a _____.
discrete probability distribution
A description of how the probabilities are distributed over the values the random variable can assume is called a(n) _____.
probability distribution
The form of the continuous uniform probability distribution is _____.
rectangular
