Unformatted text preview: corresponding sample statistic due to the fact information is collected only about a sample. The NonSampling Error refers to the difference between the population parameters and the corresponding sample statistic due to mistakes that occur when collecting, recording and tabulating the data. Sums of Random Variables Ex: Suppose you were supposed to read X pages for one class and Y pages for another class. X and Y are random variables . X + Y is also a random variable. The Expected Value of the sum of the two random variables is: E[X + Y] = E[X] + E[Y]. If X and Y are independent then the variance of the sum of the two random variables is: Var[X + Y ]= Var[X] + Var[Y]. If X and Y are independent random variables and they follow normal distributions with parameters (ux, ox^2) and (uy, oy^2) then X + Y follows a normal distribution with parameters (ux + uy, ox^2 + oy^2)....
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 Winter '10
 Bognar,K.
 Standard Deviation, Variance, Probability theory, probability density function, corresponding sample statistic

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