PAS 3

Question 1

Null hypothesis

Answer 1

states that there is no relationship between the two variable being studies and that any apparent effects are just due to random variation

Question 2

Alternative hypothesis

Answer 2

states there is a relationship between the two variables being studied and that any apparent effects are NOT due to random variation

Question 3

if the null hypothesis is true…

If the null hypothesis is false…

Answer 3

there is no real effect

the alternative hypothesis is true

• there is a relationship
• could be that experimental hypothesis is true
• could be biases in experimental design
• may be another reason

Question 4

What do significance tests do?

What do significance tests calculate?

Answer 4

compare the variation with the effect size

p-value

Question 5

What is the p-value?

Answer 5

probability that the effect size is due to random variation and there is no real effect - *tells you about the strength of your data

Question 6

p=0.001
p=0.04-0.02
p=0.01
p<0.01
p=0.05
p>0.05

Answer 6

statistically very strong data
statistically weak to moderately weak data
moderately strong data
statistically moderate to strong
statistically weak data
weak to very weak data

Question 7

If p=0.05, the probability that the null hypothesis is true is… and the probability that the alternative hypothesis is true is…

Answer 7

50% the null hypothesis is true

50% the alternative hypothesis is true

Question 8

Conditional Probability

Answer 8

The probability of an event occurring given that another has occurred. The probability of A given that B has occurred is denoted as P(A|B).

Question 9

What do we want to know from the experiment

Answer 9

The probability of our null hypothesis to be true or false, based on the data

*basically tells us whether our data is statistically weak or statistically strong

The researcher must then decide to reject or not reject the null hypothesis based on the date. There is no accepting the alternative hypothesis – it’s all about rejecting the null hypothesis.

Question 10

What does the statistical test tell us about the experiment?

Answer 10

The probability of getting data like the data we actually obtained, ASSUMING the null hypothesis is true

Question 11

What does scientific confidence come from?

Answer 11

repeating experiments

Question 12

Null Hypothesis Significance Tests

Answer 12

Z-test, T-test, and ANOVA