Reading statistics

Question 1

What is the mean?

Answer 1

The average score in a set of data

Question 2

What is the standard deviation?

Answer 2

how much scores vary on average from the mean

Question 3

What does a letter mean in descriptive stats?

Answer 3

tells you what kind of statistical model was used

Question 4

what is a t-test

Answer 4

a family of statistics that is used to look at differences between two groups (conditions)

The bigger the value, the bigger the difference between the two groups

Question 5

What are degrees of freedom?

Answer 5

indicates info about sample size and possibly how many conditions are in the study (combination of the two are important to knowing if score is significant)

Question 6

what is an r test?

Answer 6

looks at the correlation (relationship) between two variables. It is given a value between -1 and 1

Question 7

What kind of tests are there?

Answer 7

Studies where you’re looking at the differences between two groups (t test) e.g. autisim study

Studies where you’re looking at relationships and assocations between variables (r test)

Question 8

What is correlation?

Answer 8

The assoication between two variables

Question 9

What is the correlation co-efficient?

Answer 9

A value given to capture the relationship between 2 variables between -1 and 1

Question 10

What does a 0 correlation value mean?

Answer 10

weaker strengh of correlation

Question 11

What does a -1 correlation co-efficient mean?

Answer 11

perfect negative correlation

Question 12

What is a positive negative correlation?

Answer 12

When one variable increases, the other decreases

Question 13

What does a +1 correlation mean?

Answer 13

perfect positive correlation

Question 14

what is a positive correlation?

Answer 14

When the value of one variable increases (or decreases) the other increase (or decreases)

Question 15

What is d?

Answer 15

Measure of effect size, telling you how big the effect you’ve just observed is.

It is a measure of the degree to which differences in a dependent variable are attributed to the independent variable

Anything bigger than 0.8 is a large effect.

Question 16

What are the rules of thumb for r?

Answer 16

.1 - .3 = weak correlation
.3 - .5 = moderate correlation
.5 -1 = strong correlation

Question 17

What is p?

Answer 17

Probability, the likelihood that an event will occur due to chance or not.

Question 18

What are the values of p between?

Answer 18

0 and 1

Question 19

What does a p value of 0 mean?

Answer 19

an event which is absolutely certain NOT to happen

Question 20

what does a p value of 1 mean/

Answer 20

an event which is absolutely certain WILL happen

Question 21

What does a p value of 0.5 mean?

Answer 21

an event which is a likely to happen as not happen

Question 22

When does a p value become statistically significant?

Answer 22

when p< .05 , it regjects the null hypothesis (that there will not be a difference)

Question 23

when does a p value vecome non-significant?

Answer 23

when p>.05, it is non-significant and fails to reject the null hypothesis.

Question 24

what are measures of central tendency?

Answer 24

mean, medium, modal scores

Question 25

What does dispersion around the average central tendency show?

Answer 25

how the scores varied

Question 26

what is the problem with the p value?

Answer 26

doesn’t show the range of effect size

Question 27

what are the purposes of inferentail statistical tests?

Answer 27

calculates statistical significance and allows us to draw conclusions

used to determine whether changes in a dependent variable are caused by the IV

Question 28

what do descriptive statistics allow?

Answer 28

collecting analyzing and describing data

Question 29

what is a one tailed hypothesis?

Answer 29

when you have specified the direction of the relationship between variables or the difference between the two conditions.

Also called a directional hypothesis. You are pointing to the answer.

Question 30

What is a two tailed hypothesis?

Answer 30

where you have predicted that there will be a relationship between variables or a difference between the two conditions, but you have not predicted the direction of the relationship between the variables or the difference between the conditions.

Non-directional hypothesis.

Question 31

What are inferential statistics?

Answer 31

Researchers used them to demonstrate that a change in the value of a dependent variable can be attributed to a change in the value of an independent variable, rather than the chance, random variation.