Data analysis: descriptive statistics Flashcards
Descriptive statistics
-the use of graphs, tables and summary statistics to analyse sets of data
Measures of central tendency
-the general term for any measure of the AVERAGE value in a set of data
Measures of central tendency
List
Mean
Median
Mode
Mean
- the arithmetic average
- calculated by adding up all the values in a set of data
- and dividing it by the number of values there are
Mean
Evaluation
Strengths
-most sensitive, most representative
└as includes all values in data set
Limitations
-easily distorted by extreme values
Median
- the central value in a set of data
- when the values are arranged from highest to lowest
Median
Evaluation
Strengths
- not easily distorted by extreme values
- easy to calculate
Limitations
-less sensitive, less representative
└as doesn’t include all values in data set
Mode
-the most frequently occurring value in a set of data
Mode
Evaluation
Strengths
- easy to calculate
- sometimes the only method that works
Limitations
-less sensitive, less representative
└as doesn’t include all values in data set
Bi-modal data
-when a set of data had two modes
Measures of dispersion
-the general term for any measure of spread or variation in a set of data
Measures of dispersion
List
Range
Standard deviation
Range
- a simple measure of dispersion in a set of data
- calculated by subtracting the lowest score from the highest score and adding one
Range
Evaluation
Strengths
-easy to calculate
Limitations
-not always representative
Standard deviation
- a sophisticated measure of dispersion in a set of data
- it tells us how much the scores deviate from the mean
- larger the standard deviation, the greater the dispersion in a set of data
