Multiple Questions Answers

11.Online interviews of 1500 parents with children under the age of eight found the proportion who read to their children at least 20 minutes a day to be 0.78. Suppose a reporter would like to claim that more than three-fourths (0.75) of all parents with children under eight read to them at least twenty minutes daily.
What notation is used for the number 0.75?
A) p
B) p̂
C) p0
D) None of the above
12.A Type I Error is rejecting the null hypothesis, even though it is true; a Type II Error is failing to reject the null hypothesis, even though it is false.
Merck developed an AIDS vaccine that showed promise in initial tests. Unfortunately, in a subsequent test conducted internationally on a large group of volunteers, those vaccinated were no less likely to become infected than those who were not vaccinated. Apparently, Merck’s conclusion in the initial tests was
A) a Type I Error
B) a Type II Error
C) both (a) and (b)
D) neither (a) nor (b)
13.Each student in a class of 80 rolls 8 dice in order t perform inference about the mean of all dice rolls (which happens to be 3.5).
Suppose each student uses his or her sample to test the true null hypothesis that the population mean is 3.5 against the two-sided alternative. About how many of these 80 tests should reject at the α=0.05 level?
A) 0
B) 4
C) 8
D) 28
E) 52
14.Students compared tuition, in thousands of dollars, for samples of public and private colleges/universities in the US.
N Mean St. Dev SEMean
Public 5 7.26 1.48 0.66
Private 6 32.32 3.30 1.3
Difference = μ public - μ private
Estimate for differences: -25.06
T-Test of difference =0 (vs. not =): T-Value = XXXX P-Value = 0.000 DF=7
A) Paired study
B) Two-sample study
C) Both of the above
D) None of the above
15.A sleep-lab study found that a group of subjects with a mean age of about 68 years slept significantly less than the group of subjects with a mean age of 22 years, with the former averaging only 7.4 hours and the latter 8.9 hours. In contrast, an ANOVA procedure on student survey data found no significant difference in hours slept among 1st, 2nd, 3rd, and 4th year students. In general, to produce evidence of a relationship between sleep and age, which is more helpful?
A) include individuals who are all roughly the same age
B) include individuals spanning a wide range of ages
C) it doesn’t matter how similar or different the ages are
16.ANOVA was used to compare samples of weekly hotel rates at three Mexican resorts: Cancun, Puerto Vallarta, and Los Cabos.
Which of these best describes the relative rates?
A) one of the resorts was much cheaper than the other two
B) one of the resorts was much more expensive than the other two
C) all three resorts’ rates were quite similar
17.What does the null hypothesis state?
A) x̄1 = x̄2 = x̄3
B) μ1 = μ2 = μ3
18.What does the alternative hypothesis state?
A) All three population means are different
B) Not all of the population means are different
C) Not all three population means are the same
19.You are a researcher, and have set up a hypothesis test of μ. You want to compare the value of the sample mean to the value of the population mean as stated in the null hypothesis. This comparison is accomplished using the test statistic:
A) Z-test
B) F-test
C) Chi-square
20.When would you use a t-statistic vs. a z-statistic?
A) when the standard deviation is known and the sample population is normally distributed
B) when the sample population is normally distributed
C) Both a & b
D) None of the above