Statistics (Z Score)

Hypothesis Tests

Null Hypothesis

Have = sign

Alternative Hypothesis

Have ≠ sign

P value (aka probability)

Probability of P hat if null hypothesis is true

Significance Level

Percentage of probability’s unusualness

What is usually significance level

Less than 5% = unusual

Significance level symbol

Alpha

Alternative Hypothesis symbol

H1

Null Hypothesis Symbol

H0

Tests statistic is just

Z score

Z score

distance a data value is from the mean in terms of standard deviation

What kind of question is it if there are percentages

Proportion Q

When it says increase

use greater than sign

Level of significance

Probability of making Type I Error

Do you accept null hypothesis

NOOOO

Hypothesis test is just

guessing

T distribution is

centered at 0 and symmetric at 0

Confidence interval

made of interval numbers based on point estimate

Level of confidence

(1-a) - 100%

As sample size increases

margin of error decreases

Level of confidence increases

margin of error increases

More spread of the pop’s SD

Wider the interval for given level of confidence

If P-value is larger than 0.5

DONT REJECT NULL HYPOTHESIS

If p-value is LESS than 0.05

REJECT NULL HYPOTHESIS

Sample evidence can prove null hypothesis is true

FALSE

What happens to the probability of making a Type II​ error, beta​, as the level of​ significance, alpha​, ​decreases? Why?

Prob increase because Type I and Type II are INVERSELY RELATED