S2- Hypothesis Testing

Question 1

What is a population?

Answer 1

A collection of items

Question 2

What is a sampling frame?

Answer 2

A list of items in a population

Question 3

What is a census?

Answer 3

A complete enumeration of a population

Question 4

What is a sample?

Answer 4

A selection of items from a population

Question 5

What is a statistic?

Answer 5

A random variable that consists of data from just the sample

Question 6

What is the null hypothesis (H0)?

Answer 6

The working hypothesis, which is assumed to be true

Question 7

What is the alternative hypothesis (H1)?

Answer 7

One of the hypotheses that could describe the situation if H0 isn’t true

Question 8

What is a test statistic?

Answer 8

A statistic used in a hypothesis test

Question 9

What is a sampling distribution?

Answer 9

The distribution of a statistic

Question 10

What is the critical region?

Answer 10

The range of values that would lead you to reject the null hypothesis

Question 11

What is the significance level?

Answer 11

The level of probability we are prepared to accept- used to determine the critical region.

Question 12

What values does the significance level normally take in S2?

Answer 12

5% or 10%

Question 13

When is the test one-tailed?

Answer 13

when H1 is either ≥ or ≤ than p (if binomial) or λ (if Poisson)

Question 14

When is the test two-tailed?

Answer 14

when H1 is ≠ to p (if binomial) or λ (if Poisson)

Question 15

What happens to the significance level with a two-tailed test?

Answer 15

It gets halved, with half the significance level determining the lower critical region, and the other half the upper critical region

Question 16

When do you accept H0?

Answer 16

If P(X≥x) or P(X≤x) (depending on what the question asks) is more than the significance level

Question 17

When do you accept H1?

Answer 17

If P(X≥x) or P(X≤x) (depending on what the question asks) is less than the significance level

Question 18

Advantages of taking a census

Answer 18

Every member of the population is used.
It is unbiased.
It gives an accurate answer.

Question 19

Disadvantages of censuses

Answer 19

It takes a long time.
It is costly.
It is often difficult to ensure that the whole population is surveyed.

Question 20

Advantages of sampling

Answer 20

Sample will be representative if population large and well mixed.
Usually cheaper.
Essential if testing involves destruction (life of a light bulb, etc.).
Data usually more easily available.

Question 21

Disadvantages of sampling

Answer 21

Uncertainty, due to the natural variation – two samples are unlikely to give the same result.
Uncertainty due to bias prevents the sample from giving a representative picture of the population