Reference no: EM131008589
A city wants to know if a new advertising campaign to make citizens aware of the dangers of driving after drinking has been effective. They count the number of drivers who have been stopped with more alcohol in their systems than the law allows for each day of the week in the week before and the week a month after the campaign starts. Here are the results:
Day of week
|
Before
|
After
|
M
|
5
|
2
|
T
|
4
|
0
|
W
|
2
|
2
|
Th
|
4
|
1
|
F
|
6
|
8
|
S
|
14
|
7
|
Su
|
6
|
7
|
a) Are the data paired? Explain.
b) Compute the mean difference.
c) Compute the standard deviation of the differences.
d) Compute the standard error of the mean difference.
e) Find the value of the t-statistic.
f) How many degrees of freedom does the t-statistic have?
g) Is the alternative one- or two-sided? Explain.
h) What is the P-value associated with this t-statistic? (Assume that the other assumptions and conditions for in- ference are met.)
i) At a = 0.05, what do you conclude?
Expertise in statistical sampling methods
: Statistical training. The accounting firm described in Exercise 30 is interested in providing opportunities for its auditors to gain more expertise in statistical sampling methods.
|
Hot dogs and calories-hot dogs and sodium
: The Consumer Reports article de- scribed in Exercise 25 also listed the sodium content (in mg) for the various hot dogs tested. A test of the null hypothesis that beef hot dogs and meat hot dogs don't differ in the mean amounts of sodium yields a ..
|
Change from the percentage of completion method by a company
: Change from the percentage-of-completion method by a company in the long-term construction industry.
|
Standard error of the mean difference
: a) What is the standard error of the mean difference? b) How many degrees of freedom does the t-statistic have? c) What is the 90% confidence interval for the mean dif- ference? d) What do you conclude at a = 0.05?
|
Compute the mean difference
: a) Are the data paired? Explain. b) Compute the mean difference. c) Compute the standard deviation of the differences. d) Compute the standard error of the mean difference.
|
Find the path followed by a heat seeking particle
: The temperature field in the neighborhood of (π / 4, 0) is given by T(x, y) = square root 2 e-y cos (x). Find the path followed by a heat seeking particle originating at (π / 4, 0).
|
Results in number of customer visits
: They want to test the hypoth- esis that there is no mean difference in traffic against the alternative that the program increases the mean traffic. Here are the results in number of customer visits to the 10 stores:
|
Retrospective restatement usually is appropriate for a chang
: Retrospective restatement usually is appropriate for a change in :
|
Compute the value of the correlation coef?cient
: The paper "A Cross-National Relationship Between Sugar Consumption and Major Depression?" concluded that there was a correlation between re?ned sugar consumption and annual rate of major depression (cases per 100 people) based on data, Constru..
|