Research Methods

Data that is expressed in words and other non- numerical forms- descriptive data

(+) it is rich in detail- therefore is a more meaningful insight so has a high external validity

(-) it is difficult to analyse- this is because it is difficult to summarise statistically and therefore is difficult to analyse patterns and make comparisons between sets of data

Data that can be counted- it is usually numerical

(+) relatively simple to analyse and can therefore make comparisions between different sets of data and see patterns

(-) it may fail to represent real life so it has a lower external validity

Information obtained first hand by the researcher for example from participants in an experiment

(+) authentic data- is obtained direct from the source (the participants themselves)

(-) takes time and effort whereas secondary data can be accessed quickly

Information that has already been collected by another researcher that is used as part of the current research

(+) inexpensive and easily accessed- may find desired information already exists which prevents the need for further research in that area

(-) secondary data may not be of high quality/validity and the content of the data may not match the researcher's needs

Combining results from a number of studies in a particular topic to provide an overall view

The use of graphs, tables and summary statistics to identify trends and analyse sets of data

The general term for any measure of the average value in  set of data

The arithmetic average calculated by adding up all of the values in a set of data and divinding by the number of values there are

(+) it is the most sensitive measure as all the scores in the data set are used within the calculation

(-) it is easily distorted by extreme variables

The central value in a set of data when values are arranged from lowest to highest

(+) not affected by extreme scores/values

(-) less sensitive than the mean as not all scores in the data set are used in the calculation

The most frequently occuring value in a set of data

(+) easy to calculate and only method for data that is in categories

(-) doesn't represent the data set as a whole

The general term for any measure of the spread or variation in a set of data/scores

Simple calculation of the dispersion in a set of scores which is worked out by subtracting the lowest score from the highest score and usually adding 1 as a mathematical correction (allows for the fact that scores are often rounded up or down)

(+) easy to calculate

(-) only takes the two extreme values into account so may be unrepresentative of the data as a whole

A sophisticated measure of dispersion in a set of scores.
It tells us how much the scores deviate from the mean by calulating the difference between the mean and each score.

All of these differences are then added up and divided by the number of scores. This gives us the variance.

Large deviation= scores widely spread around the mean

Small deviation= scores are closely clustered around the mean

(+) more precise than range as all the scores are included in the calculation

(-) can be distorted by extreme value

A type of graph that represents the strength and direction of a relationship between co-variables in a correlation analysis.

It does not matter which variable is on which axis

A type of graph in which the frequency of each variable is represented by the height of the bars.

Visual display so it easily shows the mean values.

A symmetrical spread of frequency data that forms a bell shaped curve/pattern.

The mean, median and mode are all located at the highest peak as most of the people are located in the middle of the curve with very few at either of the ends.

A spread of frequency data that is not symmetrical and the data clusters at one end of the graph

A type of distribution in which the long tail is on the positive (right) side of the peak and most of the distribution is concentrated on the left 
For example: a difficult test where most of the scores are low and very few are high

The mode is at the highest peak

The median and mean are then progressively towards the right of the mode

A type of distribuation in which the long tail is on the negative (left) side of the peak and most of the distribution is concentrated on the right.
For example: a very easy test where most of the students score highly and very few score a low mark

The mode is at the highest peak

The median and mean are progessively towards the left of the mode