True or False: 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, the null hypothesis should be rejected at a 5% level of
significance when testing whether there is a significant relationship between the
percentage of students passing the proficiency test and the entire set of explanatory
variables.
True or False: One of the consequences of collinearity in multiple regression is inflated
standard errors in some or all of the estimated slope coefficients.
True or False: The professor of a business statistics class wanted to find out the mean
amount of time per week her students spent studying for the class. She divided the fifty
students on her roster into ten groups starting from the first student on the roster. The
first student was randomly selected from the first group. Then every tenth student was
selected from the remaining students. This is an example of a cluster sample.
True or False: The width of a confidence interval equals twice the sampling error.
True or False: If P(A or B) = 1.0, then A and B must be collectively exhaustive.
True or False: Sampling error equals half the width of a confidence interval.
The amount of time necessary for assembly line workers to complete a product is a
normal variable with a mean of 15 minutes and a standard deviation of 2 minutes. The
probability is ________ that a product is assembled in less than 12 minutes.
TABLE 12-6
According to an article in Marketing News, fewer checks are being written at the
grocery store checkout than in the past. To determine whether there is a difference in
the proportion of shoppers who pay by check among three consecutive years at a 0.05
level of significance, the results of a survey of 500 shoppers in three consecutive years
are obtained and presented below.
Referring to Table 12-6, what is the critical value?
TABLE 8-10
A sales and marketing management magazine conducted a survey on salespeople
cheating on their expense reports and other unethical conduct. In the survey on 200
managers, 58% of the managers have caught salespeople cheating on an expense report,
50% have caught salespeople working a second job on company time, 22% have caught
salespeople listing a ‘strip bar” as a restaurant on an expense report, and 19% have
caught salespeople giving a kickback to a customer.
Referring to Table 8-10, construct a 95% confidence interval estimate of the population
proportion of managers who have caught salespeople working a second job on company
time.
TABLE 2-12
The table below contains the opinions of a sample of 200 people broken down by
gender about the latest congressional plan to eliminate anti-trust exemptions for
professional baseball.
Referring to Table 2-12, of those for the plan in the sample, ________ percent were
females.
A quality control engineer is interested in estimating the proportion of defective items
coming off a production line. In a sample of 300 items, 27 are defective. A 90%
confidence interval for the proportion of defectives from this production line would go
from ________ to ________.
Referring to Table 14-17, what is the p-value of the test statistic when
testing whether age has any effect on the number of weeks a worker
is unemployed due to a layoff while holding constant the effect of the
other independent variable?
TABLE 14-17
Given below are results from the regression analysis where the
dependent variable is the number of weeks a worker is unemployed
due to a layoff (Unemploy) and the independent variables are the age
of the worker (Age) and a dummy variable for management position
(Manager: 1 = yes, 0 = no).
The results of the regression analysis are given below:
TABLE 16-4
The number of cases of merlot wine sold by a Paso Robles winery in an 8-year period
follows.
Referring to Table 16-4, a centered 5-year moving average is to be constructed for the
wine sales. The number of moving averages that will be calculated is ________.