The chi-square distribution is _____________.
A. Positively skewed
B. Negatively skewed
C. Normally distributed
D. Uniformly distributed
A recent study of the relationship between social activity and education for a sample of
corporate executives showed the following results.
The appropriate test to analyze the relationship between social activity and education is
__________.
A. A regression analysis
B. An analysis of variance
C. A contingency table analysis
D. A goodness-of-fit test
In an ANOVA table for a multiple regression analysis, the global test of significance is
based on the _________.
A. Treatment mean square divided by the error variation
B. Block and error variation
C. Treatment mean square and block mean square
D. Regression mean square divided by the mean square error
If two events A and B are mutually exclusive, what does the special rule of addition
state?
A. P(A or B) = P(A) + P(B)
B. P(A and B) = P(A) + P(B)
C. P(A and/or B) = P(A) + P(B)
D. P(A or B) = P(A) – P(B)
Sweetwater & Associates write weekend trip insurance at a very nominal charge.
Records show that the probability that a motorist will have an accident during the
weekend and file a claim is 0.0005. Suppose they wrote 400 policies for the coming
weekend, what is the probability that exactly two claims will be filed?
A. 0.8187
B. 0.2500
C. 0.0164
D. 0.0001
A company is studying the number of monthly absences among its 125 employees. The
following probability distribution shows the likelihood that people were absent 0, 1, 2,
3, 4, or 5 days last month.
What is the mean number of days absent?
A. 1.00
B. 0.40
C. 0.72
D. 2.5
A frequency distribution has a mean of 200 and a standard deviation of 20. The class
limits for one class are 220 up to 240. What are the standard normal z-statistics for the
class limits?
A. -20 and 20
B. -2.0 and -1.0
C. 200 and 220
D. 1.0 and 2.0
A supplier delivers an order for 20 electric toothbrushes to a store. By accident, three of
the electric toothbrushes are defective. What is the probability that the first two electric
toothbrushes sold will be returned because they are defective?
A. 3/20 or 0.15
B. 3/17 or 0.176
C. or 0.25
D. 3/190 or 0.01579
Which of the following is a characteristic of the F distribution?
A. Normally distributed
B. Positively skewed
C. Negatively skewed
D. Equal to the t distribution
Refer to the following distribution:
What are the class limits for class with the highest frequency?
A. 55 up to 64
B. 54 up to 64
C. 55 up to 65
D. 55 up to 64.5
David’s gasoline station offers 4 cents off per gallon if the customer pays in cash and
does not use a credit card. Past evidence indicates that 40% of all customers pay in
cash. During a one-hour period, 15 customers buy gasoline at this station. What is the
probability that more than 8 and less than 12 customers pay in cash?
A. 0.210
B. 0.212
C. 0.092
D. 0.562
Tables of normal distribution probabilities are found in many statistics books. These
probabilities are calculated from a normal distribution with ___________.
A. A mean of 1 and a standard deviation of 1
B. A mean of 100 and a standard deviation of 15
C. A mean of 0 and a standard deviation of 15
D. A mean of 0 and a standard deviation of 1
The regression equation is Ŷ = 30 + 2.56X, the sample size is 14, and the standard error
of the slope is 0.97. What is the test-statistic to test the significance of the slope?
A. z = -2.560
B. z = +2.639
C. t = +2.560
D. t = +2.639
Assuming the population variances are known, the population variance of the difference
between two means is _____________.
A. The sum of the two means
B. The sum of the two population variances
C. The sum of the two population standard deviations
D. The sum of the two sample sizes for each population
If a data set of 10 observations is used in a multiple regression analysis with 10
independent variables, then ____________.
A. The R2 will be equal to 1.0
B. The multiple standard error of the estimate will be 1.0
C. The independent variables will be correlated
D. The regression coefficients will all equal 1.0
The degrees of freedom associated with the regression sum of squares equals ____.
A. The number of independent variables
B. 1
C. The F-ratio
D. (n – 2)
The following graph is a
A. Dot plot
B. Stem-and-leaf display
C. Box plot
D. Contingency table
What is the median of 26, 30, 24, 32, 32, 31, 27, and 29?
A. 32
B. 29
C. 30
D. 29.5
The critical t statistic for an alternative hypothesis, H1: > 30, a 1% level of significance,
and a sample size of 8 is __________.
A(n) ____________ hypothesis test is indicated if the alternate hypothesis states a
direction.
When observing a checkout line at a food store, the average number of people served is
30 per hour. Using the Poisson distribution, what is the probability that no (zero) people
check out in any given hour?
When H0: is rejected in ANOVA, we compute ____________ to identify pairs of means
that differ.
To compare the effect of weather on sales of soft drinks, a distributor surveyed people
in two regions of the country and asked if they purchased soft drinks in the last month.
The following are the results. The distributor would like to know if there is a difference
in sales between the two regions.
Test the hypothesis with a 0.01 significance level. What is our decision?
For a frequency distribution of qualitative data, if the observations can be assigned to
only one class, the classes are __________________________.
The mean monthly income of a group of college students is $500; the standard
deviation is $50. And the mean monthly income is normally distributed. Approximately,
what percent of the incomes will lie between $400 and $600?
In a contingency table, multiplying the row total by the column total and dividing by
the ___________ computes the expected frequency for a cell.
The proportion of the area under a normal curve that is to the left of z = 0.50 is
_______.
We are interested in knowing if the following frequency distribution is normally
distributed. The population mean and standard deviation of the data are 600 and 160,
respectively.
If the distribution was normally distributed, what is the expected frequency for the “400
up to 600″ class?
An ANOVA comparing the waiting times for four different emergency rooms shows the
following comparison of the four mean waiting times.
Which two pairs of means are significantly different?
A sample of five full-service gasoline stations, each carrying three grades of gasoline,
was taken, and the price per liter (to the nearest cent) was recorded for each grade of
gasoline, as shown in the following table.
What is the median price of super unleaded gas?
A survey of property owners’ opinions about a street-widening project was taken to
determine if owners’ opinions were related to the distance between their home and the
street. A randomly selected sample of 100 property owners was contacted and the
results are shown next.
What are the degrees of freedom for testing the null hypothesis?
Complete the following analogy: An experiment relates to outcome, as the role of a die
relates to _____.
A company is studying the number of daily debit card purchases. There were 20
purchases and the probability of a debit card purchase is 0.5. What is the standard
deviation of the number of debit card purchases?