Fundamental concepts Flashcards
What is a hypothesis?
Statement about an unknown population parameter.
Null Hypothesis (H0)
The existing idea to test against. (Statement with no effect or difference).
Alternative Hypothesis (H1)
The challenging idea.
(Statement with effect or difference).
Type I Error (α)
Choose alternative instead of null (false positive).
Type II Error (β)
Choose null instead of alternative (false negative).
Significance Level (α)
The probability of making a Type I error, commonly 0.05.
P-value
Probability of obtaining a result, assuming the null hypothesis is true.
What do hypothesis tests check?
If the sample statistics lie in the tails of the null distribution.
Z-score
Standardized measure of the difference between the sample and hypothesized statistic.
Standard normal distribution parameters
mean = 0
std = 1
Two-tailed test
Alternative different from null
Right-tailed test
Alternative greater than null
Left-tailed
Alternative less than null
To get a p-value, use a…
Cumulative distribution function
