inferential statistics

Question 1

what is a one-tailed test

Answer 1

directional hypothesis

Question 2

what is a two-tailed test

Answer 2

non-directional hypothesis

Question 3

how to calculate the sign test

Answer 3

1. identify your categories
2. calculate the number of people in each category
3. assign the category where there is no difference a 0 sign. These participants are removed from the rest of the test
4. Assign one of the other 2 categories a + sign and a - sign
5. out of the + and - categories, identify the category with the smallest number. This is S

Question 4

Conclusion for whether results are significant

Answer 4

The calculated value of ______ is greater than/smaller than/equal to the critical value of _______ (p<________, _____ - tailed test, N =________). This means that the result is/is not significant. This means that we can accept/reject the null hypothesis that ________________________________. [If your result is significant, you then add] This means that we can accept the alternative hypothesis that _________________________________________________________. However, because the significance level was __________, there is still a _______________ probability that the results would have occurred even if _____________________.

Question 5

what is the aim of statistical testing

Answer 5

to determine the likelihood (probability) that the effect/difference/relationship/association is due to chance

Question 6

what does p<0.05 mean

Answer 6

there is a less than 5% probability that the difference/effect/relationship/association that has been found is due to chance

Question 7

benefits of statistical testing

Answer 7

• increases the scientific credibility and objectivity of research
• allows the researcher to determine whether the null hypothesis should be accepted or rejected

Question 8

what is a significance level

Answer 8

the point at which the researcher can claim to have discovered a significant difference or correlation within the data.
Or the point at which the researcher can reject the null hypothesis and accept the alternative hypothesis

Question 9

why do psychologists sometimes use stringent/lower significance levels?

Answer 9

In studies where there may be a human cost, or one-off studies that for practical reasons could not be repeated in the future

Question 10

what decisions are needed to determine which statistical test is used

Answer 10

• level of measurement
• is the study a test of difference, correlation or association?
• experimental design

Question 11

what is the difference between correlations and associations

Answer 11

• correlations are relationships where both variables are ordinal or interval data
• associations are relationships where both variables are nominal

Question 12

what is a related design

Answer 12

when matched pairs or repeated measures has been used

test of an association

Question 13

what is an unrelated design

Answer 13

when an independent groups design has been used

test of a correlation

Question 14

decision table rhyme

Answer 14

Can Simon Cowell Make Winners Sing Under Real Pressure

Question 15

How to check for a type 1 error

Answer 15

-keep the tailed test and the N/df the same
- change the significance level to the smallest one you can
- check if the calculated value is still significant or not
- if it is, a type 1 error has not been made. If it’s not, a type 1 error has likely been made

Question 16

what is a type 1 error

Answer 16

when the null hypothesis is rejected but should have been accepted because it is ‘true’
- occurs when the significance level is too lenient (p<0.10)
- the likelihood of making a type 1 error is the same as the significance level

Question 17

what is a type 2 error

Answer 17

• when the null hypothesis is accepted but should have been rejected because the alternative hypothesis is ‘true’
• occurs when the significance level is too stringent (p<0.01)

Question 18

checking for a type 1 error conclusion

Answer 18

• Currently, we are approximately ______% confident in our rejection of the null hypothesis because a ________ significance level has been used. This means that there is still a less than _____% probability of rejecting the null hypothesis when it is true and making a type 1 error. To check this, a more stringent significance level of ______ should be used which reduces the probability of a type 1 error having been made to less than ____%, making us more confident that a type 1 error hasn’t been made. When this significance level is used, the calculated value of ____ is greater than/less than/equal to the critical value of _____ (p<________, ____-tailed test, N/df = _____). This means that the result is still significant/is no longer significant. This suggests that a type 1 error has been made and so the null hypothesis should be accepted/this suggests that a type 1 error is unlikely to have been made as there is only a less than ___% probability of this and so we can be more confident in rejecting the null hypothesis.

Question 19

why is the significance level of 0.05 used

Answer 19

it is a balance between making a type 1 error and a type 2 error