Histograms- no gaps, find lower + upper boundary and class width.
Frequency density = frequency / class width
area of each bar = frequency
Stem and Leaf diagram - remember a key
Cumulative Frequency graphs - show upper class boundary and cumulative freq.
cumulative freq = y axis, upper boundaries = x axis
median = 0.5(Ecf+1) on y axis and then read across, 0.25 for lb, 0.75 for ub.
Percentiles - divide data into 100, Pn = N/100 x (total freq + 1) , where n = position
DATA - 2
Box and whisker diagrams - always draw a scale
Variance = Efx2/Ef - mean2 or Ex2/n - mean2
Standard deviation = ?/variance
For grouped data, assume every reading takes the mid-class value
Coding - y = x-b/a, My = Mx-b/a, Sy = Sx/a , where M is mean of
Skewness, PCS = 3(mean- median)/std. dev. lies between -3 and 3, with -3 as negatively skewed
Quartile skewness = Q3-2Q2+Q1/Q3-Q1
Outliers fall outside fences- method will be given in Q