quiz

Question 1

when are samples considered dependent?

Answer 1

two samples are dependent if the values in one sample are influenced by the values in the other

Question 2

what kind of dependent samples are there?

Answer 2

matched pairs (members resemble each other) and repeated measurements (same individual is measured twice)

Question 3

what is a hypothesis?

Answer 3

A statistical hypothesis is a premise or claim that we want to test, a statement about the numerical value of a population parameter(s).

Question 4

what is the test statistic?

Answer 4

A test statistic is a quantity, calculated based on a sample, whose value is the basis for deciding whether or not to reject the null hypothesis.

Question 5

what is the p-value?

Answer 5

the p-value is the smallest significance level at which a null hypothesis can be rejected, given the observed sample statistic.

Question 6

what is a type 1 error?

Answer 6

False Positive: A Type I error occurs if the researcher rejects the null hypothesis in favor of the alternative hypothesis when, in fact, H0 is true. The probability of committing a Type I error is denoted by α.

Question 7

what is a type 2 error?

Answer 7

False Negative: A Type II error occurs if the researcher fails to reject the null hypothesis when, in fact, H0 is false. The probability of committing a Type II error is denoted by β.

Question 8

can we find out if we’ve committed s type 1 error?

Answer 8

No, but the probability of making one is equal to the significance level.

Question 9

what do we have to take into account to conduct a hypothesis test for the mean?

Answer 9

1) If we are sampling from a normally distributed population
2)Whether the population variance is know.
3)Whether our sample size is large enough for the Central Limit Theorem to apply (n ≥ 30).

Question 10

what is needed to conduct a hypothesis test for proportion?

Answer 10

The sample size must be big enough: np(1-p)>5

Question 11

how do is the power function generated?

Answer 11

By computing the power of a test for all values of μ included in the alternative hypothesis

Question 12

what are the 4 features of the power function?

Answer 12

1. The farther the true mean is from the hypothesized mean μ0, the greater is the power of the test
2. The smaller the significance level (α) of the test, the smaller the power. The changes are not linear.
3. The larger the population variance, the lower the power of the test.
4. The larger the sample size, the greater the power of the test.

Question 13

True or false: We can use power to determine how large a sample is required to detect an effect of a certain size.

Answer 13

True

Question 14

True or false: Power is the ability of a test to detect an effect given that an effect of a certain size exists in a population.

Answer 14

True

Question 15

True or false: The power of a test is the probability that a given test is reliable and valid.

Answer 15

False

Question 16

True or false: The power of a statistical test depends on how strict we are about deciding that an effect is significant.

Answer 16

True

Question 17

True or false: The power of a statistical test depends on whether the test is a one-tailed or two-tailed test.

Answer 17

True