Module 9

Question 1

What are the two decisions in hypothesis testing?

Answer 1

Reject the null – when sample evidence contradicts

Do not reject the null – when sample evidence supports

Question 2

Null vs alternative hypothesis

Answer 2

Null hypothesis: assumes no effect or no difference
- i.e. in court, the defendant is innocent

Alternative hypothesis: represents a difference or effect
- i.e. the defendant id guilty

Question 3

Type I error

Answer 3

False positive
Rejecting H when it is true
i.e. convicting an innocent person
Probability = a (significance level)

Question 4

Type II error

Answer 4

False negative
Not rejecting H when it is false
i.e. letting a guilty person go free
Probability = B

Question 5

One tailed test

Answer 5

Tests for an effect in a specific direction.
Example: Testing if mean > or < a value

Question 6

Two tailed test

Answer 6

Tests for an effect in both directions.
Example: Testing if mean ≠ a value

Question 7

What are the steps for formulating hypotheses

Answer 7

Identify the null hypothesis (H0)—represents no change or difference.

Define the alternative hypothesis (H1)—represents the difference or effect being tested.

Decide if the test is one-tailed or two-tailed, based on the research question.

Question 8

What are the correct decisions in hypothesis testing?

Answer 8

Rejecting H0 when H0 is false

Not rejecting H0 when H0 is true

Question 9

Four-steps for formulating null hypothesis

Answer 9

1. Formulate hypotheses (H₀ and H₁).
2. Determine α and find the critical value.
3. Calculate test statistic (e.g., z, t).
4. State the conclusion and interpret results.