inferential statistics

Question 1

what are descriptive statistics?

Answer 1

allows us to describe and draw patterns from the data

Question 2

what is probability?

Answer 2

is the finding significant, numerical value of how likely an event is to happen
-what level of probability researchers would agree that a finding is not due to chance
- 0 to 1

Question 2

what are inferential statistics?

Answer 2

infer if your hypothesis was correct and if the data is significant

Question 3

what does significance mean?

Answer 3

• the probability that the result is down to chance is low
• the iv caused the change in dv

Question 3

what does distribution mean?

Answer 3

how spread out your data is when plotted on a frequency graph

Question 4

what is a significance level?

Answer 4

• the probability level that we accept an event is unlikely to have happened
• standard= 5%

Question 5

using the standard significance level when do we accept the null hypothesis?

Answer 5

p=>0.05= not significant
results by chance

Question 6

using the standard significance level when do we reject the null hypothesis?

Answer 6

p=<0.05= significant

Question 7

what are the non parametric tests?

Answer 7

-Mann Whitney U test
- Chi Square
-Binomial Sign Test
-Wilcoxon Signed Ranks Test
-Correlations Spearmans Rho

Question 8

when would you use a parametric test?

Answer 8

-normal distribution for data
-variances of data population should be equal
-interval data
-small range (no extreme scores)

Question 9

what phrase helps determine which non parametric test to use?

Answer 9

lions drink cola everyday
-level of data
-difference or correlations
-experimental design

Question 10

what does observed value mean?

Answer 10

calculated value
-number produced after calculations

Question 11

what does critical value mean?

Answer 11

table value
-value from statistical test table
-must be reached in order for results to be significant

Question 12

what does degrees of freedom mean? (df)

Answer 12

for chi squared test
used instead of N
-number of categories of data minus 1

Question 13

choosing a stats test
-do you have nominal data?
if yes

Answer 13

do you have the same or different participants

Question 14

choosing stats test
-do you have same or different participants?

Answer 14

same= sign test
-different= chi-squared test

Question 15

choosing stats test
-do you have nominal data
no

Answer 15

are you testing for a difference or correlation

Question 16

what test is always used for correlations?

Answer 16

spearmans rank

Question 17

if testing for a difference and no nominal data what is the next question?

Answer 17

same or different participants

Question 18

choosing stats test
-do you have same or different participants
not nominal

Answer 18

same= Wilcoxon
different= Mann Whitney U

Question 19

what is a type 1 error?

Answer 19

-false positive
-accepted alternative when results due to chance

Question 20

solution for a type 1 error?

Answer 20

more stringent significance level
(p=0.01)

Question 21

what is a type 2 error?

Answer 21

-false negative
-accepting null hypothesis when alternative correct

Question 22

solution for a type 2 error?

Answer 22

use less stringent significance level
(p=0.05)

Question 23

what is the most common significance level and why?

Answer 23

5%
balance between type1 and 2 errors
1 in 20 chance

Question 24

steps for Mann-Whitney U?

Answer 24

1) rank data across both conditions
2)add ranks for separate conditions
3)use smallest R value in formula
4)use critical table
5) U has to be equal to or below critical value to be significant and alternative hypothesis accepted

Question 25

steps for Wilcoxon test?

Answer 25

1)find differences between condition 1 and 2
*always subtract the same way
2) rank all differences and ignore signs
3)add up ranks for + and -
4)choose smaller T value
5)compare against table
6)if T<CV result is significant

Question 26

steps for Chi squared?

Answer 26

1) label cells
2)calculate expected values
3)(o-e)squared divided by e
4)total values
5)df (R-1)x(c-1)
6)check for significance

Question 27

steps for binomial sign?

Answer 27

1)direction of difference
2)least common sign
3)value table

Question 28

steps for binomial sign?

Answer 28

1)direction of difference
2)least common sign
3)value table

Question 29

steps for spearman’s rho?

Answer 29

1)rank scored each condition separate
2)find difference between the ranks for each set of data
3)square
4)add all squared
5)put data in formula
6) use table