maths

Question 1

bar charts

Answer 1

• are an easy way of representing data that is not continuous (nominal)

Question 2

histograms

Answer 2

• show frequency density on the y axis instead of the raw frequency value.
• This means they represent the data distribution far more accurately.
• The ​area​ of each bar, that is the height x width, is equal to the ​frequency.
• The x axis is represented by an interval or group of continuous data values

Question 3

pie charts

Answer 3

• use percentages to represent segments of a circle as the values associated with data groups.
• only used for continuousdata

Question 4

mean

Answer 4

• a measure of central tendency. It shows the average or expected value in a set of data.

Question 5

strengths of mean

Answer 5

• Easy to calculate mathematically, gives a precise value, useful for statistical tests.

Question 6

weakness of mean

Answer 6

• Can be affected by outliers (causing skew), can give a value not originally in the data set (unrealistic)

Question 7

median

Answer 7

The middle value in a set of data that is organised by increasing value

Question 8

strengths of median

Answer 8

• Not affected by outliers, will always give a value originally in the data set

Question 9

weakness of median

Answer 9

Not as useful for other statistical test, requires sorted and ordered data.

Question 10

mode

Answer 10

Provides the most frequent or common value in a data set.

Question 11

strengths of mode

Answer 11

• A useful way of calculating the average when the data is nominal

Question 12

weakness of mode

Answer 12

There may be multiple modes, there may not be a mode at all, the mode may not represent the spread of the data in an accurate way

Question 13

range

Answer 13

A measure of dispersion - the difference between the highest and lowest value in a set of data

Question 14

strength of range

Answer 14

Easy to calculate and gives a good idea of the spread of data.

Question 15

weakness of range

Answer 15

Is affected by outliers and is not useful for other statistical calculations.

Question 16

calculate the variance

Answer 16

• Calculate the mean of the data in the table
• Subtract the mean from every value in the table - this new value is
  called ‘d’
• Square each value of ‘d’
• Add up each value of ‘d squared’
• Divide this number by N - the number of values in the table

Question 17

calculate standard deviation

Answer 17

• Calculate the mean of the data in the table
• Subtract the mean from every value in the table - this new value is
  called ‘d’
• Square each value of ‘d’
• Add up each value of ‘d squared’
• Divide this number by N - the number of values in the table
• square root your answer to give SD

Question 18

what correlation is this scatter graph?

Answer 18

• positive correlation

Question 19

what correlation is this scatter graph?

Answer 19

• moderate negative correlation

Question 20

what correlation is this scatter graph?

Answer 20

• strong positive correlation

Question 21

what correlation is this scatter graph?

Answer 21

• no linear relationship

Question 22

positive relationship

Answer 22

as one variable increases in value, so does the other
e.g hours of revision and percentage score on a maths test

Question 23

negative relationship

Answer 23

• as one variables increases, the other decreases e.g hours watching television and percentage score on a maths test

Question 24

parametric tests

Answer 24

assume that the population that the data is drawn from is normally distributed.

Question 25

non-parametric tests

Answer 25

- used when this assumption cannot be made. - In psychological experiments, these tests are often used due to difficulty in gaining normally distributed populations.

Question 26

what skew is this

Answer 26

normal skew

Question 27

what skew is this

Answer 27

positive skew

Question 28

what skew is this

Answer 28

negative skew

Question 29

interquartile range

Answer 29

- the difference between the upper and lower quartiles - shows the spread within data once separated into 4 equal groups

Question 30

standard deviation

Answer 30

- shows the average difference between the data values and the mean. - The standard deviation can therefore indicate the overall dispersion as a large standard deviation highlights that each value varies quite significantly from the mean. - The standard deviation is a better measure than the range if there are outlying scores as it considers all the items in the distributions and is less affected by anomalous data.

Question 31

quantitiative data

Answer 31

- data that is measured and expressed numerically, such as a value, amount or quantity. - It is usually associated with units. - extremely useful for using directly with statistical tests and usually involves a very structured form of data collection, for example, measurements of temperature.

Question 32

qualitative data

Answer 32

- describes the attributes and qualities of data rather than defining it with measurements. - extremely useful at providing depth of information and can therefore develop a more meaningful understanding.

Question 33

primary data

Answer 33

data collected directly and originally from the researchers themselves with the purpose of using the data in the experiment itself.

Question 34

secondary data

Answer 34

research data that was collected by a third party at a previous time, possibly for use in another experiment, but that is still useful for the research purpose.