Hypotheses
What does the symbol Ho represent?
Null Hypothesis
How many outcomes are there in a hypothesis test?
2 outcomes:
Reject the null hypothesis
Fail to reject (support) the null hypothesis
How many types of tests are there?
Three:
Left-tailed
Right-tailed
Two-tailed
What is the first step of performing calculations in a hypothesis test?
Determine the type of test (right-tailed, left-tailed, two-tailed).
What value is considered the "magic number" in statistics? (The value that your p-value must be lower than in order to reject the null hypothesis)
0.05
What does the symbol Ha represent?
Alternative Hypothesis
What is a Type I error?
Rejecting the null hypothesis when the null hypothesis is actually correct.
How do you know if a test is left-tailed?
The alternative hypothesis uses the "less than" symbol (<).
What is the second step of performing calculations in a hypothesis test?
Calculating the z-score.
You conduct a hypothesis test and calculate a p-value of 0.01. Would you reject or support the null hypothesis?
Reject the null hypothesis (p-value is less than 0.05).
If H0 was M = 3, what would Ha be?
M is not equal to 3.
What is a Type II error?
Failing to reject (supporting) the null hypothesis when the null hypothesis was actually incorrect.
Ho: Starbucks grande drink is 16 ounces.
Ha: Starbucks grande drink is less than 16 ounces.
Left-tailed
What is the third step of performing calculations in a hypothesis test?
Use the z-table to determine the p-value.
You conduct a hypothesis test and calculate a p-value of 0.08. Would you reject or support your null hypothesis?
Support the null hypothesis (p-value is greater than 0.05).
Starbucks claims that their grande drinks are 16 ounces. We want to test if it is actually less.
Ho: Average grande drink is 16 ounces (M = 16).
Ha: Average grande drink is less than 16 ounces (M < 16).
Ho: A certain medicine is safe to use.
Ha: A certain medicine is not safe to use.
What is the Type I error?
Rejecting that the medicine is safe, when the medicine is actually safe.
Ho: Average test score is 80.
Ha: Average test score is higher than 80.
Right-tailed
What is the z-score formula for a mean?
See board.
What is a p-value?
Probability of obtaining your sample outcome if the null hypothesis is true.
A study shows that 12% of people are left-handed. We want to test if that study is true.
Ho: Proportion of left-handed people is 12% (p = 0.12).
Ha: Proportion of left-handed people is not 12% (p is not equal to 0.12).
Ho: A certain medicine is safe to use.
Ha: A certain medicine is not safe to use.
Which error is worse to make in this case?
Type II Error:
Supporting that the medicine is safe, when it is actually not safe to use.
Ho: A certain medicine is safe to use 95% of the time.
Ha: A certain medicine is not safe to use 95% of the time.
Two-tailed
What is the z-score formula for a proportion?
See board.
When making your conclusion statements, what should you always provide in order for the conclusion to make sense?
Context! Relate your conclusion statement back to the original problem.