Stats

Question 1

+LR

Answer 1

change in likelihood that a patient has the condition after a positive test

Question 2

-LR

Answer 2

change in likelihood that a patient does not have condition after a negative test

Question 3

t-tests

Answer 3

statistical hypothesis test used to determine if 2 sets of data are significantly different from one another

Can be Unpaired/Paired or 1 tailed/2 tailed

Question 4

Null Hypothesis

Answer 4

you are always testing null with p-values

there is no significant difference between groups
u1 = u2

Question 5

Alternate Hypothesis

Answer 5

there is a significant difference between groups OR group 1 is significantly greater/less than group 2

u1 does not equal u2
u1>u2 OR u1<u2

Question 6

Research Hypothesis

Answer 6

could be either the null of the alternative hypothesis
you initial guess when starting an experiment

Question 7

Unpaired/Independent samples t-test

Answer 7

Groups are independent, not the same people

Question 8

Paired/dependent samples t-test

Answer 8

groups are the same people, generally pre vs post test

Question 9

1 Tailed T-Test

Answer 9

directional
looks for an increase or decrease, testing either greater OR less

Question 10

2 Tailed T Tests

Answer 10

looks for a change
tests both greater AND less than
stronger test

Question 11

Alpha Level

Answer 11

value you set as the researcher, usually .05

the probability that you will commit a type 1 error
a lower alpha level means you are taking a smaller risk that you will report an effect when there is actually no effect

Question 12

Type 1 error

Answer 12

reporting an effect when there is no effect
False positive

Question 13

Type 2 error

Answer 13

reporting no effect when there is an effect
False negative

Question 14

p-value

Answer 14

value that is obtained with t-test
compared to alpha level to determine significance

Question 15

If p value is < alpha level

Answer 15

reject the null, significant difference between groups

Question 16

if p value is > alpha level

Answer 16

fail to reject the null, no difference between the groups

Question 17

Hypothesis rules

Answer 17

your options are: fail to reject the null, reject the null

you NEVER accept the null
you NEVER accept or reject the alternative hypothesis

Question 18

p-hacking

Answer 18

the more t-tests you run, the greater chance you will get a significant result

can be abused by researchers

Question 19

One-way ANOVA

Answer 19

used to determine whether there are any statistically significant differences between the means of three or more independent/unrelated groups

used with unpaired t test

Question 20

Repeated Measures ANOVA

Answer 20

used to determine if there are significant differences within the same group over time

used with paired t test

time is almost always an independent variable

Question 21

Post Hoc Testing

Answer 21

tells you which groups or time points are different after doing a pvalue and t-test

Question 22

Power

Answer 22

the probability that a test of significance will pick up on an effect that is present, probability that a test of significance will detect a deviation from the null hypothesis, should such a deviation exist

1-Type 2 Error = power