TABLE 13-4
The managers of a brokerage firm are interested in finding out if the number of new
clients a broker brings into the firm affects the sales generated by the broker. They
sample 12 brokers and determine the number of new clients they have enrolled in the
last year and their sales amounts in thousands of dollars. These data are presented in the
table that follows.
Referring to Table 13-4, the managers of the brokerage firm wanted to test the
hypothesis that the number of new clients brought in had a positive impact on the
amount of sales generated. At a level of significance of 0.01, the decision that should be
made implies that the number of new clients brought in ________ (‘had’ or ‘did not
have’) a positive impact on the amount of sales generated.
TABLE 3-1
Health care issues are receiving much attention in both academic and political arenas. A
sociologist recently conducted a survey of citizens over 60 years of age whose net
worth is too high to qualify for Medicaid. The ages of 25 senior citizens were as
follows:
Referring to Table 3-1, determine the interquartile range of the ages of the senior
citizens.
TABLE 10-6
To investigate the efficacy of a diet, a random sample of 16 male patients is selected
from a population of adult males using the diet. The weight of each individual in the
sample is taken at the start of the diet and at a medical follow-up 4 weeks later.
Assuming that the population of differences in weight before versus after the diet
follow a normal distribution, the t-test for related samples can be used to determine if
there was a significant decrease in the mean weight during this period. Suppose the
mean decrease in weights over all 16 subjects in the study is 3.0 pounds with the
standard deviation of differences computed as 6.0 pounds.
Referring to Table 10-6, if we were interested in testing against the two-tail alternative
that D is not equal to zero at the = 0.05 level of significance, the null hypothesis
would ________ (be rejected/not be rejected).
TABLE 8-14
The superintendent of a unified school district of a small town wants to make sure that
no more than 5% of the students skip more than 10 days of school in a year. A random
sample of 145 students from a population of 800 showed that 12 students skipped more
than 10 days of school last year.
Referring to Table 8-14, what is the upper bound of the 95% one-sided confidence
interval for the proportion of students who skipped more than 10 days of school last
year?
TABLE 17-8
The superintendent of a school district wanted to predict the percentage of students
passing a sixth-grade proficiency test. She obtained the data on percentage of students
passing the proficiency test (% Passing), daily mean of the percentage of students
attending class (% Attendance), mean teacher salary in dollars (Salaries), and
instructional spending per pupil in dollars (Spending) of 47 schools in the state.
Following is the multiple regression output with Y = % Passing as the dependent
variable, X1 = % Attendance, X2 = Salaries and X3 = Spending:
Referring to Table 17-8, what is the p-value of the test statistic when testing whether
instructional spending per pupil has any effect on the percentage of students passing the
proficiency test, taking into account the effect of all the other independent variables?
TABLE 18-7
A supplier of silicone sheets for producers of computer chips wants to evaluate her
manufacturing process. She takes sample sizes of 5 from each day’s output and counts
the number of blemishes on each silicone sheet. The results from 20 days of such
evaluations are presented below.
She also decides that the upper specification limit is 10 blemishes.
Referring to Table 18-7, what percentage of the chips will fall below the upper
specification limit?
TABLE 16-5
The number of passengers arriving at San Francisco on the Amtrak cross-country
express on 6 successive Mondays were: 60, 72, 96, 84, 36, and 48.
Referring to Table 16-5, the number of arrivals will be exponentially smoothed with a
smoothing constant of 0.25. The smoothed value for the second Monday will be
________.
TABLE 19-5
The following payoff table shows profits associated with a set of 2 alternatives under 3
possible events.
Suppose that the probability of Event 1 is 0.2, Event 2 is 0.5, and Event 3 is 0.3.
Referring to Table 19-5, what is the opportunity loss for Action B with Event 3?
TABLE 3-7
In a recent academic year, many public universities in the United States raised tuition
and fees due to a decrease in state subsidies. The change in the cost of tuition, a shared
dormitory room, and the most popular meal plan from the previous academic year for a
sample of 10 public universities were as follows: $1,589, $593, $1,223, $869, $423,
$1,720, $708, $1,425, $922 and $308.
Referring to Table 3-7, what are the (absolute values of) the Z scores of the change in
cost?