Statistical tests Flashcards
1
Q
What is nominal data
A
- represented in categorical forms
- e.g. male and female
- discrete data- item can only appear in one category
2
Q
What is ordinal data
A
- ordered in some way e.g. rating scale
- e.g. first, second and third in a race
- lacks precision as ordering is subjective
- unsafe data- the raw scores need converting into rants to use in the test
3
Q
What is interval data
A
- based on numberical scales with equal units
- uses scales of measurements e.g. stopwatch, thermometer, weighting scales
- most precise
4
Q
What are inferential tests and how can we use them
A
- try to infer from the sample data what the population might think
- allow psychologists to draw conclusions from their findings
- these conclusions are based on the probability that a particular pattern of results could have arisen by chance or not
- findings NOT due to chance=significant
5
Q
What probability do psychologists use and why
A
- 95%- means there is a 5% chance of the results occurring if null hypothesis is true
- probability of 5% recorded at p<0.05
6
Q
Equal to or less than?- explain
A
- the probability should be EQUAL TO OR LESS THAN 5% (p<0.05)
- meaning there is a 5% chance thta it is not significant
7
Q
If you have SIGNIFICANT results do you which hypothesis do you accept/reject
A
- reject null
- accept alternative
8
Q
What are critical values
A
the numerical boundary between acceptance and rejection of the null hypothesis
9
Q
What is the degree of freedom
A
n-1
10
Q
What is a type 1 error
A
- false positive
- incorrect rejection of null- need to accept instead
- optimistic error- claiming to have found significant results when they are not
- most likely if significant level is too lenient e.g. 0.05
11
Q
What is a type 2 error
A
- false negative
- incorrently accepted null- need to reject instead
- pessimistic error- claiming to have found insiginificant results
- most likely if significant level is too stringent e.g. 0.01
12
Q
What do we need to know about our data in order to tell whether we have significance
A
- level of measurmeent
- type of hypothesis
- experimental design
