If a data set has SST 2,000 and SSE 800, then the coefficient of determination is
a. 0.4
b. 0.6
c. 0.5
d. 0.8
The number of customers at Winkies Donuts between 8:00a.m. and 9:00a.m. is believed
to follow a Poisson distribution with a mean of 2 customers per minute.
a. During a randomly selected one-minute interval during this time period, what is the
probability of 6 customers arriving to Winkies?
b. What is the probability that at least 2 minutes elapse between customer arrivals?
Exhibit 21-3
From a population of size 600, a simple random sample of size 58 is selected. The
sample mean is 400, and the sample standard deviation is 40.
Refer to Exhibit 21-3. An approximate 95% confidence interval for the population mean
is
a. 395 to 405
b. 380 to 420
c. 360 to 440
d. 390 to 410
The expected value of a discrete random variable
a. is the most likely or highest probability value for the random variable
b. will always be one of the values x can take on, although it may not be the highest
probability value for the random variable
c. is the average value for the random variable over many repeats of the experiment
d. All of the answers are correct.
A life insurance company has determined that each week an average of seven claims is
filed in its Nashville branch.
a. Define the random variable in words for this experiment.
b. What is the probability that during the next week exactly seven claims will be filed?
c. What is the probability that during the next week no claims will be filed?
d. What is the probability that during the next week fewer than four claims will be
filed?
e. What is the probability that during the next week at least seventeen claims will be
filed?
Bivariate probabilities are often called
a. union probabilities
b. conditional probabilities
c. marginal probabilities
d. joint probabilities
A simple random sample of size n from a finite population of size N is to be selected.
Each possible sample should have
a. the same probability of being selected
b. a probability of 1/n of being selected
c. a probability of 1/N of being selected
d. a probability of N/n of being selected
Exhibit 18-5
Forty-one individuals from a sample of 60 indicated they oppose legalized abortion. We
are interested in determining whether or not there is a significant difference between the
proportions of opponents and proponents of legalized abortion.
Refer to Exhibit 18-5. The conclusion is that there
a. is no significant difference between the proportions
b. is a significant difference between the proportions
c. could be a difference in proportions, depending on the sample size
d. None of these alternatives is correct.
Which of the following symbols represents the standard deviation of the population?
a. 2
b.
c.
d.
The average age in a sample of 90 students at City College is 20. As a result of this
sample, it can be concluded that the average age of all the students at City College
a. must be more than 20, since the population is always larger than the sample
b. must be less than 20, since the sample is only a part of the population
c. could not be 20
d. could be larger, smaller, or equal to 20
When using Excel’s POISSON.DIST function, one should choose TRUE for the third
input if
a. a probability is desired
b. a cumulative probability is desired
c. the expected value is desired
d. the correct answer is desired
In order to test the hypotheses H0: 100 and Ha: 100 at an level of
significance, the null hypothesis will be rejected if the test statistic z is
a.
b.
c. –
d. 100
To avoid the problem of having access to tables of the F distribution with values for the
lower tail when a one-tail test is required, let
a. the smaller sample variance be the numerator of the test statistic
b. the larger sample variance be the numerator of the test statistic
c. the sample variance from the population with the smaller hypothesized variance be
the numerator of the test statistic
d. the sample variance from the population with the larger hypothesized variance be the
numerator of the test statistic
Which of the following is not an example of descriptive statistics?
a. a histogram depicting the age distribution for 30 randomly selected students
b. an estimate of the number of Alaska residents who have visited Canada
c. a table summarizing the data collected in a sample of new-car buyers
d. the proportion of mailed-out questionnaires that were returned
Exhibit 18-5
Forty-one individuals from a sample of 60 indicated they oppose legalized abortion. We
are interested in determining whether or not there is a significant difference between the
proportions of opponents and proponents of legalized abortion.
Refer to Exhibit 18-5. The null hypothesis should be
a. rejected
b. not rejected
c. Not enough information is given to answer this question.
d. None of these alternatives.
In a cumulative percent frequency distribution, the last class will have a cumulative
percent frequency equal to
a. one
b. 100
c. the total number of elements in the data set
d. None of the other answers are correct.
If we want to provide a 95% confidence interval for the mean of a population, the
confidence coefficient is
a. 0.485
b. 1.96
c. 0.95
d. 1.645