Unformatted text preview: f significance, does this recent experience suggest a decline in spending? Determine and interpret the p
value for the test. 1
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7 A
zTest of a Me an
S ample me an
P opula tion st andard dev iation
S ample size
Hypothesized mean
Alpha B 4.20
1.80
18
5.00
0.05 C z St at
P(Z<=z) onetail
z Critical oneta il
P(Z<=z) tw otail
z Critical t wotail D 1 .89
0.0 297
1.645
0.0 593
1.960 PROBLEM # 8.13
Based on the sample data, a confidence interval has been constructed such that we have 90% confidence that the population mean is between 120 and 180. Given this information, provide the conclusion that would be reached for each of the following hypothesis tests at the ! =0.10 level: a. H0:! =170 versus H1:!
b. H0:! =110 versus H1:!
c. H0:! =130 versus H1:!
d. H0:! =200 versus H1:! ≠170 ≠110 ≠130 ≠200 5 PROBLEM # 8.14 Under what circumstances should the t
statistic be used in carrying out a hypothesis test for the population mean? PROBLEM # 8.15 For a simple random sample of 40 items, ! =25.9 and s=4.2. At the 0.01 level of significance, test H0:! =24.0 versus H1:! ≠24.0 PROBLEM # 8.16 For a simple random sample of 15 items from a population that is approximately normally distributed, ! =82.0 and s=20.5. At the 0.05 level of significance, test H0:! ≥90.0 versus H1:! <90.0. 6 1
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7 A
tTest of a Mean
Sample mean
Sample standard deviation
Sample size
Hypothesized mean
Alpha B C 82.0
20.5
15
90.0
0.05 D t Stat
P(T<=t) onetail
t Critical onetail
P(T<=t) twotail
t Critical twotail 1.511
0.076
1.761
0.153
2.145 PROBLEM # 8.17
The International Coffee Association has reported the mean daily coffee consumption for U.S. residents as 1.65 cups. Assume that a sample of 38 people from a North Carolina city consumed a mean of 1.84 cups of coffee per day, with a standard deviation of 0.85 cups. In a two
tail test at the 0.05 level, could the residents of this city be said to be significantly different from their counterparts across the nation? Source: coffeeresearch.org, August 8, 2006. 1
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7 A
tTest of a Mean
Sample mean
Sample standard deviation
Sample size
Hypothesized mean
Alpha B 1.84
0.85
38
1.65
0.05 C t Stat
P(T<=t) onetail
t Critical onetail
P(T<=t) twotail
t Critical twotail D 1.378
0.088
1.687
0.177
2.026 PROBLEM # 8.18 When carrying out a hypothesis test for a population proportion, under what condition is it appropriate to use the normal distribution as an approximation to the (theoretically correct) binomial distributio...
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 Fall '08
 GHATRI
 Standard Deviation, the00, Engineer00

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