Maths in psychology

Question 1

What is an extraneous variable?

Answer 1

Any variable other than the IV that may have an effect on the DV if it is not controlled

Question 2

What is a confounding variable?

Answer 2

Any variable other than the IV that can affect the DV so that we cannot be sure of the true sources of the changes on the DV

Question 3

What are demand characteristics?

Answer 3

Any cue from the researcher that may be interpreted by the participants as revealing the purpose of the investigation. Participants may change their behaviour within the research situation

Question 4

What are investigator effects?

Answer 4

Any effects of the researchers behaviour on the DV

Question 5

What is randomisation and why would you use it?

Answer 5

The use of chance in order to control for the effects of bias when designing materials and deciding the order of conditions

Question 6

What is standardisation and why would you use it?

Answer 6

Using exactly the same formalised procedures and instructions for all participants in the research study. To make sure the outcome is uninfluenced by other stimuli.

Question 7

How do you control for extraneous variables?

Answer 7

Standardisation and randomisation

Question 8

What are the measures of central tendency?

Answer 8

Mode, Mean, Median

Question 9

Why would you use the mean?

Answer 9

The mean is the most sensitive measure, it uses all the scores and values which means it is more representative of all the data

Question 10

Why might you not use the mean?

Answer 10

It is distorted by extreme values / outliers meaning the mean might not really reflect the data overall

Question 11

Why would you use the median?

Answer 11

Extreme scores do not affect it. It is also easy to calculate once all the data is in order.

Question 12

Why would you not use the median?

Answer 12

It is less sensitive than the mean because not all the data values are represented.

Question 13

When would you use the mode?

Answer 13

For some data, which is categorical, the mode is the only way to measure the data. You would count the frequency for each category

Question 14

Why would you not use the mode?

Answer 14

It is a crude measure, it doesn’t represent the data fairly

Question 15

What are the measures of dispersion? (2)

Answer 15

Range, Standard deviation

Question 16

Why would you use the range?

Answer 16

It is easy to calculate

Question 17

What is a limitation using the range?

Answer 17

It only takes into account the two most extreme scores, so is unlikely to be representative of the data

Question 18

When would you use standard deviation?

Answer 18

When precisely measuring dispersion

Question 19

Why would you use standard deviation?

Answer 19

It tells us how scores are away from the mean

Question 20

What is a problem with standard deviation?

Answer 20

Affected by extreme scores

Question 21

What must you include on a graph?

Answer 21

Labelled X & Y axis, accurately drawn, A title that includes the IV & DV

Question 22

What is the difference between a bar graph and a histogram?

Answer 22

Bar graphs are used for discreet data, Histograms are used for continuous data

Question 23

Define a normal distribution and draw it

Answer 23

A symmetrical spread of frequency data that forms a bell-shaped pattern. The mean, median and mode are all located at the highest peak.

Question 24

Define a negative skewed distribution and draw it

Answer 24

The long tail is on the left side of the peak. Most of the distribution is concentrated on the right.

Question 25

Define a positively skewed distribution and draw it

Answer 25

The long tail is on the right side of the peak. Most of the distribution is concentrated on the left.