week 7: Descriptive statistics Flashcards
name 7 types of categorical variables
1) frequency/ percentage
2) cross tabulation
3) pictogram
4) bar chart
5) cluster bar chart
6) pie chart
7) wordcloud
List the 4 measures of central tendency under continuous variables
MEASURE OF CENTRAL TENDENCY
v Mean – average of a set of values
v Median – value that divides the ordered sample into two
equal pieces
v Mode – value which occurs most frequently
v Histogram – graphical representation of the distribution
of continuous data
what does range mean:
Range – difference between the maximum and minimum
what does “ mean” means:
v Mean – average of a set of values
what does median mean?
Median – value that divides the ordered sample into two equal pieces
what does mode mean?
v Mode – value which occurs most frequently
what is histogram?
v Histogram – graphical representation of the distribution
of continuous data
what is interquartile range?
v Interquartile range – difference between the third (75%)
and first (25%) quartile of the data
what does Variance σ2 mean?
v Variance σ2 – how far a set of numbers is spread out
what does Standard deviation (SD or σ) mean?
Standard deviation (SD or σ) – square root of variance
what should you use to read the central location of a normal histogram?
MEAN
what should you use to read the central location of a skewed histogram?
median
which 2 factors determine the shape of normal distribution regarding the spread and central position.
Two things determine the shape of the normal
distribution: spread is determined by the variance
(σ2) while the central position is determined by the
mean (μ).
what is the formula to calculate 99% data, 95% data and 68% data?
~99% data would fall in the region (μ -3σ, μ +3σ)
~95% data would fall in the region (μ -2σ, μ +2σ)
~68% data would fall in the region (μ - σ, μ + σ)
