W7 Practice Quiz Questions

Question 1

Which of the following is a disadvantage of using a high significance level?

Answer 1

There is an increased probability of rejecting the null hypothesis even though it is true.

Question 2

In which of the following situations would the Central Limit Theorem apply?

Answer 2

We have as the population all wētā living on a particular island. We take a random samples of 50 wētā and find the mean length of the sample.

Question 3

All other factors being held constant, would a larger sample size increase or decrease the test statistic of the sample mean?

Answer 3

It would increase it.

Question 4

If we fail to reject the null hypothesis even though it is not true, what is that called?

Answer 4

A Type II error.

Question 5

what has a large standard error

Answer 5

when the sample size and standard deviation are similar values

Question 6

In which of the following situations would the Central Limit Theorem apply?

Answer 6

• n > 30
• normally distributed
• numerical continuous variables

Question 7

As the standard deviation increases and the sample size is kept constant, what happens to the standard error?

Answer 7

It increases.

Question 8

In which of the following situations would the Central Limit Theorem NOT apply?

Answer 8

n<30

Question 9

what does the test statistic for the sample mean tell us? e.g -2.34

Answer 9

The mean of this sample is 2.34 standard errors below the hypothesised mean.

Question 10

Which of the following is a potential problem with having very small datasets?

Answer 10

You may not have enough power to detect a difference, even if one is present.

Question 11

when is it not appropriate to perform a t-test for paired differences

Answer 11

• outliers present
• not normally distributed
• not unimodal
• not symmetrical

Question 12

If the null hypothesis assumes that there is no disease present, then a Type I error is …

Answer 12

A false positive result.

Question 13

If we decrease the significance level of a particular hypothesis test

Answer 13

we are more likely to make a Type II error.

Question 14

What does this test statistic for the sample mean tell you?

Answer 14

How many standard errors the sample mean is from the population mean.

Question 15

If we are sampling from a single population, what happens to the standard error as our sample size gets bigger?

Answer 15

It becomes smaller.

Question 16

what should I do to make the test more likely to produce a false positive than a false negative.

Answer 16

We would choose a larger significance level and increase the chance of making a Type I error

Question 17

If the null hypothesis assumes that there is no disease present, then a Type II error is …

Answer 17

A false negative result.

Question 18

What is the relationship between the probability of making a Type I error and the probability of making a Type II error?

Answer 18

As the probability of a Type I error increases, the probability of a Type II error decreases and vice versa.

Question 19

what courses a bigger power

Answer 19

larger sample size