Vocabulary
What does H₀ stand for?
Null hypothesis
What does a confidence interval estimate?
A population parameter
What test compares two population proportions?
Two-sample z-test
Samples should be chosen how?
Randomly
If 0 is NOT in a confidence interval, what does it suggest?
There is likely a significant difference
What does Hₐ stand for?
Alternative hypothesis
What critical value is usually used for a 95% z-interval?
1.96
What test compares two population means?
Two-sample t-test
What condition checks if samples are independent?
10% condition
Which test uses z-values?
Two-sample z-test
What is a p-value?
Probability of getting results this extreme if H₀ is true
What happens if 0 is in the confidence interval for a difference?
There may be no significant difference
If p-value < α, what do we do?
Reject H₀
What theorem helps assume normality for large samples?
Central Limit Theorem
Which test uses t-values?
Two-sample t-test
What does “reject H₀” mean?
There is convincing evidence for Hₐ
Which interval is used for comparing two proportions?
Two-sample z-interval
Common alpha level used in statistics?
0.05
For proportions, what must be at least 10?
Successes and failures
What does “convincing evidence” usually mean in stats?
Reject H₀
What is a Type I error?
Rejecting H₀ when it is actually true
Which interval is used for comparing two means?
Two-sample t-interval
What does a very small p-value mean?
Strong evidence against H₀
For means, sample sizes are usually greater than what number?
30
What is a Type II error?
Failing to reject H₀ when it is false