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Flashcards in Graphs Deck (8)
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what are the two types of variables and whats the difference?

categorical and numerical. caterogorical are qualitative and have no numerical signficance, whereas numerical are quantitative and do have numerical significance


whats a dot plot?

graph where the data points are represented by dots


whats a histogram?

represents both numerical and caterogorical data, where classes are used to group similarly categorised data together


what are some words used to describe histograms and what do they mean?

symmetric- self explanatory
bimodal- two peaks
unimodal-one peak
bell shaped- if symmetric and unimodal
skewed to the right- tail is on the right, and vice versa


what two things are used to numerically analyse histograms?

mean of centre and measure of varability


what is the measure of centre?

represented by the arithmetic mean of the observation values, given by 1/n*sum(from 1 to n) Xi


what is measure of variability?

represented by the sample variance, given by 1/(n-1) * sum(from 1 to n) (Xi-Xbar)^2, where n is the sample space, and Xi-Xbar represents the diff between the vaue of a data point and the average value


what is the standard deviation?

square root of the variance