Research Methods Y1 - Descriptive Statistics Flashcards
Define descriptive statistics.
The use of graphs, tables, and summary statistics to identify trends and analyse sets of data.
Define measures of central tendency.
The general term for any measure of the average value in a set of data.
Define mean.
The arithmetic average calculated by adding up all the values in a set of data and dividing by the number of values there are.
Define median.
The central value in a set of data when values are arranged from lowest to highest.
Define mode.
The most frequently occurring value in a set of data.
Define measures of dispersion.
The general term for any measure of the spread or variation in a set of scores.
Define range.
A simple calculation of the dispersion in a set of scores which is worked out by subtracting the lowest score from the highest score and adding 1 as a mathematical correction.
Define standard deviation.
A sophisticated measure of dispersion in a set of scores. It tells us how much scores deviate from the mean by calculating the difference between the mean and each score. All the differences are added up and divided by the number of scores. This gives the variance. The standard deviation is the square root of the variance.
What is one advantage and one limitation of the mean?
Advantage: Includes all of the scores/values in the data set within the calculation, making it more representative of the data as a whole.
Limitation: It is easily distorted by extreme values.
How is the median calculated?
By arranging the scores in order (from lowest to highest) and finding the middle value. If there is an even number of scores, the median is halfway between the two middle scores.
What is one advantage and one limitation of the median?
Advantage: Extreme scores do not affect it.
Limitation: The median is less sensitive than the mean because not all scores are included in the calculation.
What is one advantage and one limitation of the mode?
Advantage: It is relevant to categorical data where the mean and median cannot be used.
Limitation: It is not a useful way of describing data when there are several modes.
What is one advantage and one limitation of the range?
Advantage: It is easy to calculate.
Limitation: It is affected by extreme values and fails to account for the distribution of numbers.
How is standard deviation calculated?
By calculating the difference between the mean and each score, adding up these differences, and dividing by the number of scores to get the variance. The standard deviation is then the square root of the variance.
What does a large standard deviation suggest?
That not all participants were affected by the IV in the same way.
