Research methods 5: Probability and Significance

Question 1

What is an aim?

Answer 1

A general statement about the purpose of the experiment/investigation

Question 2

What is a hypothesis?

Answer 2

A precise testable statement about what is expected to happen in the study- IV and DV need to be included operationalised

Question 3

What is an experimental hypothesis?

Answer 3

A predict of what change will take place in the dependant variable when the independent variable is manipulated

Question 4

What is a null hypothesis?

Answer 4

A hypothesis that there is no significant difference between populations

Question 5

If the results of the study are significant we…

Answer 5

Accept the experimental hypothesis and reject the null hypothesis

Question 6

If the results of the study are not significant we…

Answer 6

Accept the null hypothesis and reject the experimental hypothesis

Question 7

What is a one tailed hypothesis?

Answer 7

A hypothesis that specifies a direction

Question 8

What is a two tailed hypothesis?

Answer 8

A hypothesis that specifies that significant results will occur, regardless of direction

Question 9

What is probability?

Answer 9

The likelihood that the results are due to chance or not

Question 10

How is probability represented in data form?

Answer 10

As P=……

Question 11

In order for the results to be significant in psychology the results need to be less than…

Answer 11

p = 0.05 (P<0.05)

Question 12

How likely are results to be due to chance when the results are significant at the P < 0.05 level?

Answer 12

5 percent

Question 13

What is the purpose of sign tests?

Answer 13

To determine whether something is significant and whether our results can be generalised.

Question 14

The criteria for using a sign test are:

Answer 14

-Looking for a difference
-Use a repeated measures design
-Data needs to be nominal data

Question 15

How do you find the S value?

Answer 15

Identify the least frequently occuring sign, so the smallest value.

Question 16

What do you do once you found the value of S?

Answer 16

Compare the number to another number called the critical value, found on the table provided

Question 17

What 4 values are needed to find the critical value?

Answer 17

-The significance value you are using (typically 0.05)
-Number of participants in the study (called N)
-Whether the hypothesis is directional or non-directional
-You need to read the rules at the bottom of the table

Question 18

If S = 1 and the Critical value = 7, what would the results be

Answer 18

We would say that the results are significant, because the critical value is more than the calculated value

Question 19

When reporting a sign test what format is used?

Answer 19

Since the calculated S value of _ is less than the critical table of , when N =, for a __=tailed, the results are significant/non significant at the P<0._ level. This means that we can accept the experimental/null hypothesis and the null/experimental hypothesis can be rejected. It was found that…

Question 20

What is a type 1 error?

Answer 20

Where a psychologist incorrectly accepts the experimental hypothesis and rejects the null hypothesis, when they should not as the result was due to chance.

Question 21

What is a type 2 error?

Answer 21

Where a psychologist incorrectly rejects the experimental hypothesis and accepts the null hypothesis when they should not as the results weren’t due to chance.

Question 22

What are type 1 and type 2 errors known as?

Answer 22

Type 1- False positive
Type 2- False negative

Question 23

What are the three significance levels?

Answer 23

-0.01 Stringent
-0.05 Balance
-0.10 Lenient

Question 24

What does a lenient significant level mean?

Answer 24

-It would be too lenient and result in many researchers making a type 1 error, less likely to make a type 2

Question 25

What does a stringent significance level mean?

Answer 25

It doesn’t leave much room for error, so psychologists would be more likely to make a type 2 error, less likely to make a type 1

Question 26

Why do we use 0.05 level of significance?

Answer 26

It’s the common significance level in psychology because it balances ths out and minimises the chances of making type 1 and type 2 errors.