INFERENCES AND LINEAR REGRESSION - BUSINESS
Questions 1 to 20:
Select the best answer to each question. Note that a question and its answers may be split across a pagebreak, so be sure that you have seen the
entirequestion andallthe answers before choosing an answer.1.
Which of the following statements aretrueregarding the simple linear regression modelyi=?0+?1xi+?
i?A.
?iis a nonrandom error.B.
?1is they-intercept of the regression line.C.
?0is the slope of the regression line.D.
yiis a value of the dependent variable(y)andxiis a value of the independent variable(x).2.
The object on which the response and factors are observed is calledA.
treatments.B.
experimental unit.C.
factor level.D.
factors.3.
A chi-square test for independence with 8 degrees of freedom results in a test statistic of 18.21. Usingthe chi-square table, the
mostaccurate statement that can be made about thep-value for this test is thatA.
p-value < 0.01.B.
0.025 >p-value > 0.01.C.
0.05 >p-value > 0.025.D.
0.10 >p-value > 0.05.4.
In testing for the equality of two population variances, when the populations are normally distributed, the10% level of significance has been used. To determine the rejection region, it will be necessary to refer to
the
Ftable corresponding to an upper-tail area ofA.
0.10.B.
0.05.C.
0.90.D.
0.20.5.
TheF-statistic in a one-way ANOVA represents the variationA.
between the treatments plus the variation within the treatments.B.
within the treatments minus the variation between the treatments.C.
within the treatments divided by the variation between the treatments.D.
between the treatments divided by the variation within the treatments.6.
With larger and larger numbers of categories in chi-square tests, the chi-square distribution takes on theshape of the _______ distribution.
A.
t-B.
binomialC.
PoissonD.
normal7.
In testing the difference between two population means using two independent samples, the samplingdistribution of the sample mean difference
x?1?x?2is normal if theA.
population sizes are both greater than 30.B.
sizes are both greater than 30.C.
populations are nonnormal and the sample sizes are large.D.
populations are normal.8.
An indication of no linear relationship between two variables would be a coefficient ofA.
correlation of 0.B.
determination equal to 1.C.
correlation equal to?1.D.
determination equal to?1.9.
A random sample of males and females involved in rear-end accidents results in the following Minitabsummary:
What is the standard error of the statistic between the two means?
N MEAN MEDIAN TRMEAN STDEV SEMEAN
FEMALES 33 23.91 20.00 23.38 9.77 1.70
MALES 38 28.87 28.50 28.44 9.67 1.57
A.
2.314B.
4.96C.
1.635D.
0.89710.
Lily Energy Systems manufacturer's wood-burning heaters and fireplace inserts. One of its systems hasan electric blower, which is thermostatically controlled. The blower is designed to automatically turn on
when the temperature in the stove reaches 125°F and turn off at 85°F. Complaints from customers indicate
that the thermostat control is not working properly. The company feels that the thermostat is acceptable if
the variance in the cutoff temperature is less than or equal to 175. The company takes a sample of 24
thermostats and finds that the variance equals 289. The calculated chi-square test statistic and the table
value for a 0.05 significance level are
A.
38.076, 38.99.B.
35.172, 38.99.C.
37.983, 38.076.D.
37.983, 35.172.11.
In a hypothesis test for the population variance, the alternate hypothesis is the population variance doesnot equal 17.0. The significance level to be used is 0.05 and the sample size to be taken is 25. The table
value(s) to use from the chi-square distribution is/are
A.
39.364.B.
12.401 and 39.364.C.
40.647.D.
13.120 and 40.647.12.
A "best-fit" mathematical equation for the values of two variables,xandy,is calledA.
regression analysis.B.
correlation analysis.C.
errors of prediction.D.
scatter diagram.13.
Given the significance level 0.025, theF-value for the degrees of freedom,df= (7,3) isA.
8.45.B.
27.67.C.
14.62.D.
5.89.14.
A random sample of males and females involved in rear-end accidents results in the following Minitabsummary:
What is the value of the test statistic (
Zscore)?N MEAN MEDIAN TRMEAN STDEV SEMEAN
FEMALES 33 23.91 20.00 23.38 9.77 1.70
MALES 38 28.87 28.50 28.44 9.67 1.57
A.
1.64B.
?2.14C.
2.32D.
?4.9615.
Given the significance level 0.05, theF-value for the degrees of freedom,df= (3,7) isA.
6.16.B.
4.12.C.
4.35.D.
8.89.End of exam
16.
Consider the following data values of variablesxandy.Find the least squares regression line.
x
4 2 6 4 3y
5 3 7 6 5A.
1.659 + 0.932xB.
1.122 + 1.073xC.
?1.045 + 0.932xD.
21.206 + 1.073x17.
A left-tail area in the chi-square distribution equals 0.95. Fordf= 10, the table value equalsA.
15.987.B.
18.307.C.
20.483.D.
3.940.18.
The vertical distances between observed and predicted values ofyare calledA.
scatterplots.B.
errors of prediction.C.
methods of least squares.D.
least square lines.19.
In testing a population variance or constructing a confidence interval for the population variance, anessential assumption is that
A.
the population is uniformly distributed.B.
the population is normally distributed.C.
sample size exceeds 30.D.
expected frequencies equal or exceed 5.20.
A balanced experiment requires thatA.
the number of treatments equals the number of samples.B.
at least one sample equal size is 30.C.
at least two treatment groups be used.D.
an equal number of persons or test units receives each treatment.
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Solution: INFERENCES AND LINEAR REGRESSION - BUSINESS