Quantitative data analysis - Descriptive statistics Flashcards
Measures of central tendency are and mean what?
Mode - The most frequent value, median - the middle value when the scores are arranged in ascending or descending order and mean - average of the all the data sets.
Mode advantages -
+ Unaffected by extreme scores, represents a figure that occurs in the data set giving useful insight.
Mode disadvantages -
- Does not tell us anything about the other values in the set of data, The mode may become less useful if there are other values that also have the same frequency (May become bimodal or multimodal. So the mode becomes less useful
Median advantages -
+ Remains unaffected by any outlying values and can be used on data with skewed distributions.
Median disadvantages -
- It ignores most of the scores in the rest of the data, doesn’t work as well with small sets of data.
Mean advantages -
+ Makes use of all data in the set and therefore is the most powerful measurement of central tendency.
Mean disadvantages -
- Cannot be used by nominal data and can easily be affected by extreme values such as anomalies and therefore affect the the data as a whole.
Brief reminders about level of measurements for example what kind of data is being portrayed -
3 types, nominal, ordinal and interval/ratio.
N - Data are in separate categories, grouping of people into their favourite football team.
O - Data are ordered in some way like asking football teams to be listed in order.
I - Data is measured using units of equal intervals, such as counting correct answers.
R - True zero point in most measures of physical quantities.
Measures of dispersion are?
Range and standard deviation.
Range strength -
Easy to calculate
Range limitations -
Affected by extreme values and doesn’t tell us a anything about the scores of the middle set.
Standard deviation strengths -
- Takes all values into account and easy if have a calculator
