Significance Tests: Practice for Test

Some people say that more babies are born in September than in any other month. To test this claim, you take a simple random sample of 150 students at your school and find that 21 of them were born in September. What is the p-value for the test?

.006

Your particular sample had 38 out of 50 students who owned Apricot mp3 players. If you were testing the null hypothesis Ho: p = .65 against the alternative Ha: p ≠.65, what would be the P-value for your sample statistic?

.103

Significance level is α = 0.05 and the power is 0.90. What is the probability of a type II error?

10%

Significance level is α = 0.05 and the power is 0.90. What is the probability of a type I error?

5%

"Do more than half of all adults think TV is less moral than society?" To do this, we would take as our hypotheses

Ho: p = 0.5 Ha: p > 0.5

Some people say that more babies are born in September than in any other month. To test this claim, you take a simple random sample of 150 students at your school and find that 21 of them were born in September. What does the p-value measure?

The probability of getting a sample with a proportion of September birthdays this far or farther above 1/12 if Ho is true is [p-value].

The power of a statistical test of hypotheses is

the probability that a significance test will reject the null hypothesis when a particular alternative value of the parameter is true.

The null hypothesis is

usually a statement of "no effect" or "no difference"

If a significance test gives P-value 0.005,

we do have good evidence against the null hypothesis.

Some people say that more babies are born in September than in any other month. To test this claim, you take a simple random sample of 150 students at your school and find that 21 of them were born in September. What are the appropriate hypotheses?

Ho: p = 1/12 Ha: p > 1/12

The mean area µ of the several thousand apartments in a new development is advertised to be 1300 square feet. A tenant group thinks that the apartments are smaller than advertised. What are the appropriate hypotheses?

Ho: µ = 1300 Ha: µ < 1300

A test of significance produces a P-value of 0.024. Which of the following conclusions is appropriate?

Reject Ho at the α = .05 level; fail to reject at the α = .01 level.

Suppose that in fact 62% of all adults favor balancing the budget over cutting taxes. The number 62% is

a parameter.

If we reject the null hypothesis, when in fact, it is true, we have

committed a Type I error.

You construct a 95% confidence interval or a mean & find it to be 1.1±0.8. If Ho: µ = 0 and Ha: µ ≠ 0, what can you conclude?

reject Ho at α = 0.05

The most important condition for sound conclusions from statistical inference is usually

that the data can be thought of as a random sample from the population of interest.