Inferential statistics

Question 1

Why are IS used?

Answer 1

When collecting data as part of research, a psy will always find a diff or relationship between measures. IS are used by researchers to establish if the diffs/ relationships are sig (large) enough to support their research hypotheses or whether they could have juts happened by chance - thus you can state that any diff/ relationship is due to chance in ur null hypothesis.

Question 2

probability level definition?

Answer 2

a numerical measure of the likelihood that somehing could happen. e.g. P<0.05

Question 3

Significance level definiton?

Answer 3

This is a level of probability that a diff/ relationship between sets of data occurred by chance. the sig level determines when a researcher will accept their research hypothesis, which is generally accepted as 0.05. However, some researchers will want to have a more strict level of sig such as 0.005

Question 4

what is a level of significance represented by?

Answer 4

P and then ,= ect

Question 5

If the results of a study are equal to ot less than the sig level, then?

Answer 5

the researcher can be confident they did not occur by chance and accept their research hypothesis.

Question 6

if the results are higher than the significance level, then?

Answer 6

chance may ahve played a part and they accept their null hypothesis

Question 7

Observed value is?

Answer 7

the number calculated using the ST and is compared to the CV to establish if there is a sig diff or correlation between the 2 or more sets of data.

Question 8

When will the OV also be the correlation coefficient?

Answer 8

• when establishing sif using A Spearman Rank Order Correlation Coefficient Test or Chi squared test

Question 9

What is the letter symbolising the OV for Chi Squared test?

Answer 9

X(^2)

Question 10

What is the letter symbolising the OV for Mann Whitney U test?

Answer 10

U

Question 11

What is the letter symbolising the OV for Sign test?

Answer 11

S

Question 12

What is the letter symbolising the OV for Spearman Rank order Correlation coefficient?

Answer 12

R

Question 13

What is the letter symbolising the OV for Wilcoxon Signed Matched Pairs ?

Answer 13

T

Question 14

Critical value: -

Answer 14

The value to which the observed value is compared to establish if it is significant. Critical values are located on a critical value table

Question 15

To identify a critical value for all tests except the Mann

Whitney U test, use the following steps:

Answer 15

1. Establish if you are carrying out a one-tailed or two-tailed test. A one-tailed test supports a directional hypothesis and two-tailed test
   supports a non-directional hypothesis.
2. Find the appropriate significance level using the one-tailed or two-tailed test level of significance row.
3. Identify your N value (df value if you are using a Chi Squared test) which is the number of sets of data and generally the number of participants in the left hand column.
4. Your critical value can be found using the significance level column and the N value row.

Question 16

to identify critical value for the Mann Whitney IJ use the

following steps:

Answer 16

1.Find the appropriate critical
value table using the desired
significance level and whether
you need a one or two-tailed
test
2.Identify your N value (number of scores, usually number of participants) for condition 1 in the top row and the N value for condition 2 in the first column.
3. Your critical value can now be found using the appropriate N1 (sometimes Na) column and N2

Question 17

Five steps to using inferential statistics to establish if the research hypothesis or null:

Answer 17

1. select appropiate sig level
2. identify an appropriate sig level test
3. calc OV
4. Compare OV to CV to establish if data is sig
5. accept or reject null and research hypothesis

Question 18

identifying an aprpriate statistical test?

Answer 18

1. Do / need a test showing the difference between my conditions or a relationship between co variables?
2. If a test of difference what experimental design did I use (repeated measures, matched pairs or independent groups)?
3. What level of data was being measured in my study (nominal, ordinal, interval or ratio)?

Question 19

identifying an appropriate statistical test 3 Ds?

Answer 19

difference
design
data

Question 20

ST and if OV needs to be higher or lower than CV for sig?

Answer 20

Sign test: lower
Wilcoxon Matched Pairs Signed Ranks test: lower
Mann Whitney U test: lower
Chi squared: higher
Spearman’s rank order correlation coefficient: higher

Question 21

ST and if OV needs to be higher or lower than CV for sig tip?

Answer 21

remember Chi rhymes w high and you throw a spear high

Question 22

always?

Answer 22

LINK TO SCENARIO

Question 23

To Accept or reject research and null hypothesises

Answer 23

• if your observed value in
  comparison to your critical value is significant then you can accept your research (experimental or alternate) hypothesis and reject your null hypothesis.
• If it is not significant then you accept your null hypothesis and reject your research hypothesis.