What is a Type I error Explain how the cumulative Type I error(attachment)
1-What is a Type I error? Explain how the cumulative Type I error
affects your decision making. How are the two independent sample t-tests
different from ANOVA?
2-Why is the F distribution important? How do you determine if a
significant difference exists among the groups in ANOVA? How do you determine
differences between the groups in ANOVA?
Describe the requirements that must be met before an ANOVA test
may be used. Discuss what the researcher must do if one of these requirements
is not met.
10.30 In 1999, a sample of 200 in-store
shoppers showed that 42 paid by debit card. In 2004, a sample of the same size
showed that 62 paid by debit card. (a) Formulate appropriate hypotheses to test
whether the percentage of debit card shoppers increased. (b) Carry out the test
at a = .01. (c) Find the p-value. (d) Test whether normality may be assumed.
10.44
Does lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack?
In a Texas study, researchers gave lovastatin to 2,325 people and an inactive
substitute to 2,081 people (average age 58). After 5 years, 57 of the
lovastatin group had suffered a heart attack, compared with 97 for the inactive
pill. (a) State the appropriate hypotheses. (b) Obtain a test statistic and
p-value. Interpret the results at a = .01. (c) Is normality assured? (d) Is the
difference large enough to be important? (e) What else would medical researchers
need to know before prescribing this drug widely? (Data are from Science News
153 [May 30, 1998], p. 343.)
10.46 To test the hypothesis that students who finish an exam
first get better grades, Professor Hardtack kept track of the order in which
papers were handed in. The first 25 papers showed a mean score of 77.1 with a
standard deviation of 19.6, while the last 24 papers handed in showed a mean
score of 69.3 with a standard deviation of 24.9. Is this a significant
difference at a = .05? (a) State the hypotheses for a right-tailed test. (b)
Obtain a test statistic and p-value assuming equal variances. Interpret these
results. (c) Is the difference in mean scores large enough to be important? (d)
Is it reasonable to assume equal variances? (e) Carry out a formal test for
equal variances at a = .05, showing all steps clearly.
11.24 In a bumper test,
three types of autos were deliberately crashed into a barrier at 5 mph, and the
resulting damage (in dollars) was estimated. Five test vehicles of each type
were crashed, with the results shown below. Research question: Are the mean
crash damages the same for these three vehicles? Crash
Damage $
Goliath
Varmint
Weasel
1600
1290
1090
760
1400
2100
880
1390
1830
1950
1850
1250
1220
950
1920
11.24 In a bumper test, three types of autos were deliberately crashed into a barrier at 5 mph, and the resulting damage (in dollars) was estimated. Five test vehicles of each type were crashed, with the results shown below. Research question: Are the mean crash damages the same for these three vehicles? Crash Damage $
Goliath
Varmint
Weasel
1600
1290
1090
760
1400
2100
880
1390
1830
1950
1850
1250
1220
950
1920
