The Kruskal-Wallis one-way analysis of variance by ranks is especially appropriate to
test whether three or more population means are equal if the data is measured with an
ordinal scale and/or the populations are not normal.
A point estimate is a single value used to estimate a population parameter.
A statistics professor wants to compare grades in two different classes of the same
course. This is an example of a paired sample.
Nonparametric tests require no assumptions about the shape of the population
distribution.
There are four levels of measurement: qualitative, quantitative, discrete, and
continuous.
The geometric mean is the nth root of n observations.
When using the t distribution to calculate a confidence interval, we assume that the
population of interest is normal or nearly normal.
If the null hypothesis states that there is no difference between the mean income of
males and the mean income of females, then the test is one-tailed.
A coin is tossed four times. The joint probability that all four tosses will result in a head
is or 0.25.
If we want to determine which treatment means differ, we compute a confidence
interval for the difference between each pair of means.
A frequency distribution for qualitative data has class limits.
Assuming that the null hypothesis is
A c-bar chart shows the percent of the production that is defective.
If we select 100 persons from 25,000 registered voters and question them about
candidates and issues, the 100 persons are referred to as the population.
If the expected value of stock purchases under conditions of certainty is $1,900 and the
expected value of stock purchases under conditions of uncertainty is $1,840, then the
$60 difference is called the value of perfect information.
If the past data approximates a straight line, the equation used is Ŷ = a + bt, where a is
the Y-intercept and b is the slope of the line.
Refer to the following distribution of commissions:
What is the relative frequency for those salespersons that earn from $1,600 up to
$1,800?
A. .02
B. .024
C. .20
D. .24
What statistics are needed to draw a box plot?
A. The minimum, maximum, median, first and third quartiles.
B. The median, mean, and standard deviation.
C. The median and interquartile range.
D. The mean and standard deviation.
The results of a mathematics placement exam at two different campuses of Mercy
College follow:
What is the null hypothesis if we want to test the hypothesis that the mean score on
Campus 1 is higher than on Campus 2?
A. H0: 1 = 0
B. H0: 2 = 0
C. H0: 1 = 2
D. H0: 1 ≤ 2
University officials say that at least 70% of the voting student population supports a fee
increase. If the 95% confidence interval estimating the proportion of students
supporting the fee increase is [0.75, 0.85], what conclusion can be drawn?
A. Seventy percent is not in the interval, so another sample is needed.
B. Seventy percent is not in the interval, so assume it will not be supported.
C. The interval estimate is above 70%, so infer that it will be supported.
The mean or expected value for a binomial probability distribution is _________.
A. μ = nÏ€(1 – Ï€)
B. μ = Ï€(1 – Ï€)
C. μ = Ï€n(1 – n)
D. μ = nπ
The regression equation is Ŷ = 29.29 – 0.96X, the sample size is 8, and the standard
error of the slope is 0.22. What is the test-statistic to test the significance of the slope?
A. z = -4.364
B. z = +4.364
C. t = -4.364
D. t = -0.960
The following graph illustrates _______________.
A. A positive or direct relationship
B. A negative or inverse relationship
C. No relationship
D. A distribution for a single variable
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 at least 10 pay in cash?
A. 0.024
B. 0.033
C. 0.009
D. 0.976
A large oil company is studying the number of gallons of gasoline purchased per
customer at self-service pumps. The mean number of gallons is 10.0, with a standard
deviation of 3.0 gallons. The median is 10.75 gallons. What is Pearson’s coefficient of
skewness in this instance?
A. -1.00
B. -0.75
C. +0.75
D. +1.00
The value of the correlation coefficient (r):
A. can be equal to the value of the coefficient of determination (r2).
B. can never be equal to the value of the coefficient of determination (r2).
C. can range from -2.0 to +2.0.
D. is generally larger than the value of the coefficient of determination.
A survey includes a question regarding marital status that has the following responses:
single, married, divorced, separated, or widowed. What is the scale of measurement for
this question?
A. Ratio
B. Interval
C. Ordinal
D. Nominal
Six basic colors are used in decorating a new condominium. They are applied to a unit
in groups of four colors. One unit might have gold as the principal color, blue as a
complementary color, red as the accent color, and touches of white. Another unit might
have blue as the principal color, white as the complementary color, gold as the accent
color, and touches of red. If repetitions are permitted, how many different units can be
decorated?
A. 7,825
B. 25
C. 125
D. 1,296
A sample of wires coming off the production line was tested for tensile strength. The
statistical results (in PSI) were the following:
According to the Empirical rule, the middle 95% of the wires tested had a tensile
strength between approximately what two values?
A. 450 and 550
B. 460 and 540
C. 420 and 580
D. 380 and 620
In a Poisson distribution, the variance is equal to ___________.
A. nπ
B.
C. e-x
D.
For the normal distribution, the mean plus and minus two standard deviations will
include about what percent of the observations?
A. 50%
B. 99.7%
C. 95%
D. 68%
Refer to the following information from a frequency distribution for “heights of college
women” recorded to the nearest inch: the first two class midpoints are 62.5″ and 65.5″.
What is the class interval?
A. 1″
B. 2″
C. 2.5″
D. 3″
What are the critical z-values for a two-tailed hypothesis test if α = 0.01?
A. 1.960
B. 2.326
C. 2.576
D. 1.645
The expected value under conditions of uncertainty subtracted from the expected value
under conditions of certainty will result in:
A. the value of perfect information.
B. an expected opportunity loss.
C. an expected monetary value.
D. an expected decision strategy.
How is a p-value related to the significance level when the null hypothesis is rejected?
A multiple regression analysis showed the following results of the individual
independent variables.
In stepwise regression, which independent variable would most likely be added first?
The capacities of several metal containers are 38, 20, 37, 64, and 27 liters. What is the
range in liters?
A company wants to study the effect of an employee’s length of employment on their
number of workdays absent. The company collected the following information on a
random sample of seven employees.
What is the dependent variable (Y)?
The “lowest” level of measurement is ___________.
For the following data, how many observations are in the data?
The relationship between interest rates as a percent (X) and housing starts (Y) is given
by the linear equation Ŷ = 4094 – 269X. What will be the number of housing starts if
the interest rate is 8.25%?
When testing the null hypothesis that two population means are equal, the hypothesized
difference between the population means is ________________.