Review of Descriptive Statistics CE 308 Civil Engineering Synthesis I
RELATIVE Frequency Frequency / total observations, n
f(x) 1 2 3 4 x
f(x) + 1 2 3 4 x
f(x) + 1 2 3 4 x
CDF 1 pdf
CDF = Cumulative Distribution Function F(x) p(X < x) non-exceedence pdf = Probability Distribution Function f(x) p(X = x)
Probability Non-Exceedence Probability Exceedence Probability
Mean, x
Measures of Central Tendency Mean Center of gravity Median Half the values of x are smaller and half are larger Mode Value of x with the largest frequency
Mean, x WHY (x-x)2
Non-Symmetric Symmetric
Negative Skew
Positive Skew
Normal
Normal Distribution