Question

If a court acquits every defendant, they will never commit a Type I error.
A) True
B) False



2.
The probability of rejecting a true null hypothesis increases as the sample size increases.
A) True
B) False



3.
For a given level of significance, the critical value of Student's t increases as n increases.
A) True
B) False



4.
In a two-tailed hypothesis test with á = .05, a test statistic of t = 1.813 with d.f. = 15 leads one to reject the null hypothesis of a statistical test.
A) True
B) False



5.
The power of a test is the probability that the test will reject a false null hypothesis.
A) True
B) False



6.
The height of the power curve shows the probability of accepting a true null hypothesis
A) True
B) False



7.
Which is not true of p-values?
A) When they are small, we want to reject Ho.
B) They must be specified before the sample is taken.
C) They show the chance of Type I error if we reject Ho.
D) They do not require á to be specified a priori.



Use the following scenario to answer questions 8 to 10.
Dullco Manufacturing claims that its alkaline batteries last forty hours on average in a certain type of portable CD player. Tests on a random sample of 18 batteries showed a mean battery life of 37.8 hours with a standard deviation of 5.4 hours.


8.
The test statistic is
A) -1.980
B) -1.728
C) -2.101
D) -1.960



9.
In determining the p-value for reporting the study's findings, which of the following is true?
A) The p-value is less than .05.
B) The p-value is equal to .05.
C) The p-value is greater than .05.
D) The p-value cannot be determined without specifying á.



10.
In a left-tailed test at á = .05 we would
A) comfortably reject the claim.
B) comfortably accept the claim.
C) feel uncomfortable with either decision (too close).
D) switch to alpha of 0.01 for a more powerful test.



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Use the following scenario to answer questions 11 to 13.

A TV special said there is a 10 per cent incidence of sexually transmitted disease (STD) among all U.S. teens. A reporter for the Rockville Bugle, looking for a story, surveyed 260 randomly chosen teenagers, and found that 39 had been to a clinic for STD treatment. Use a right-tail test at á = .05.


11.
The test statistic is
A) 2.687
B) 2.758
C) .0256
D) 2.258



12.
The critical value is
A) 1.645
B) 1.658
C) 1.697
D) 1.960



13.
The p-value is
A) .0501
B) .0314
C) 2.258
D) .0036



14.
Which of the following statements is correct?
A) For a given level of significance, the critical value of Student's t increases as n increases.
B) A test statistic of t = 2.131 with d.f. = 15 leads to a clear-cut decision in a two-tailed test where á = .05.
C) It is harder to reject the null hypothesis when conducting a two-tailed test rather than a one-tailed test.
D) If we desire á = 0.10 then a p-value of 0.13 would lead us to reject the null hypothesis.



15.
John rejected a null hypothesis in a right-tailed test for a mean at á = .025 because his critical t value was 2.000 and his calculated t value was 2.345. We can be sure that
A) John did not commit Type I error.
B) John did not commit Type II error.
C) John committed neither Type I nor Type II error.
D) none of the above can definitely be concluded.

Answer 1

The very least you should learn from the study of a subject is how to spell it. These questions are about statistics. "Statics" is a topic in basic civil engineering (mechanics of non-moving rigid bodies).

Answer 2

Dullco Manufacturing claims that its alkaline batteries last forty hours on average in a certain type of portable CD player.

Answer 3

what are the answers for questions 1-12

Answer 4

In a left-tailed test at á = .05 we would
A) comfortably reject the claim.
B) comfortably accept the claim.
C) feel uncomfortable with either decision (too close).
D) switch to alpha of 0.01 for a more powerful test.

Answer 5

4. a
5.b
6.b
7.d

Answer 6

a
a
b
a
c