Section 5: ANALYSING DATA

Question 1

Measure of central tendency

Answer 1

A single summary score that represents a whole set of scores.
- How descriptive stats are summarized

Question 2

Mode

Answer 2

Most occurring score in a distribution - add up all the scores and tally scores

Question 3

Bimodal distribution

Answer 3

When there are two frequency occurring scores

Question 4

Mean

Answer 4

The average within the distribution - all scores added together and then divided by number of.

Question 5

Median

Answer 5

The middle score in the distribution - write down all the scores starting from the lowest, and find the middle number. If there is an even number of scores the median is the average of the middle two scores.

Question 6

Regression towards the mean

Answer 6

When variables that are extremely high or low, tend to move closer to the average upon retesting.
- Ex: You achieve a lower than normal test score. You would be tempted to try to establish explanations as to why, and possibly change strategies, however it is important to consider that the same combination that resulted in that low grade won’t happen again, and the next set of results will regress back to your normal grade mean.

Question 7

Percentile rank

Answer 7

The percentage of scores that are less than a given score. So if for example, you are in the ‘79th percentile’ in a Maths competition, your score is higher than 79 %of your peers.

Question 8

Range

Answer 8

The gap between the lowest and highest scores, calculated by the largest score minus the
smallest score.
A simplified measure of variation.

Question 9

Standard deviation

Answer 9

A computed measure of how much scores vary around the mean score. The standard deviation is better because it more accurately gauges whether scores are close together or dispersed as it uses information from each score. The higher the standard deviation, the more spread out the distribution.

Question 10

Normal Distribution (aka Bell Curve)

Answer 10

0= Middle
+-1 SD= 34.13%
+-2 SD= 13.59%
+-3 SD= 2.14%
Total = 99.72%

Question 11

Positively Skewed Distribution

Answer 11

Skewed to the left
- The mean is always the highest score

Question 12

Negatively Skewed Distribution

Answer 12

Skewed to the right
- The mean is always the lowest score

Question 13

Positive correlation

Answer 13

The presence of one thing predicts the presence of the other i.e. as chocolate consumption increases, happiness levels increase.

Question 14

Negative correlations

Answer 14

The presence of one thing predicts the absence of the other i.e. as levels of homework increase, levels of happiness decrease.

Question 15

Scatterplot

Answer 15

The line of best fit (also known as the regression line), is the line drawn on a scatter plot to show the relationship.
- Correlations are represented on a scatterplot
- Visual representation of the relationships or associations between two numerical variables

Question 16

Correlation Coefficient

Answer 16

A number between -1 and 1 that tells you the strength and direction of a relationship between variables
- Correlations can be strong or weak. The strength of a correlation (aka its effect size) can be computed by a statistic called the correlation coefficient.

Question 17

Effect size

Answer 17

The strength of a correlation

Question 18

Directionality problem

Answer 18

It cannot tell us which variable is the cause and which is the effect.

Question 19

Statistical significance

Answer 19

(p-value) Tells us the likelihood of the difference(s) found between the experimental and control conditions, being caused by chance.
- We want differences to be caused by our
manipulation—the IV—not by chance. To say that the results of an experiment are statistically significant means that there is a a high likelihood they were caused by the IV. The threshold for statistical significance is no more than a 5% likelihood the results were caused by chance.
We express this as: p ≤ .05

Question 20

Institutional Review Boards

Answer 20

Ensure all research complied with the following ethical guidelines

Question 21

Right to withdraw

Answer 21

Participants have the right to withdraw at any time, regardless of whether or not they were paid.

Question 22

Deception

Answer 22

Information must not be withheld from participants, nor should they be misled

Question 23

Protection of participants from physical and psychological harm

Answer 23

Psychologists have a responsibility for
protecting their participants from physical or mental harm.

Question 24

Informed Consent

Answer 24

When someone consents to participate in research, their consent must be informed, i.e. the aims of the research should be made clear. Where the research involves children under the age of 16, then consent must be obtained from parents or guardians of the child.

Question 25

Informed Assent

Answer 25

A process through which minors can agree to participate in clinical trials. This is different from informed consent, because minors cannot provide consent in the full meaning of the word, as they don’t meet the legal age requirements and are considered to be a vulnerable population.

Question 26

Confidentiality and anonymity

Answer 26

Participants have the right to confidentiality. Names should not be used and instead numbers can be given.

Question 27

Debriefing

Answer 27

Following an investigation, participants should be fully informed about the nature of the research.