Mean and SD Calculation PDF
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Uploaded by VibrantWichita
Government College University Lahore
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Summary
This document explains mean and standard deviation calculations. It provides formulas and an example of calculating the mean and standard deviation from a dataset. The dataset used in the example is ph values of wastewater samples.
Full Transcript
Mean: The mean is the average of the numbers. Standard deviation The standard deviation is a measure of the spread of scores within a set of data OR It is Measure of dispersement in statistics. “Dispersement” tells you how much your data is spread out. Specifically, it shows you how much your...
Mean: The mean is the average of the numbers. Standard deviation The standard deviation is a measure of the spread of scores within a set of data OR It is Measure of dispersement in statistics. “Dispersement” tells you how much your data is spread out. Specifically, it shows you how much your data is spread out around the mean or average. Data Set Example: pH values of a wastewater sample at different time intervals 2 3 0 1 2 Mean (Average): 2+3+0+1+2/5 = 8/5 = 1.6 Median: 0 1 2 2 3 Mode: More frequently used data set (value or number) = 0 1 2 2 3 = 2 Standard Deviation = S = SD = SDev. X (Score) x̅ (Mean) X- x̅ (X- x̅)2 2 1.6 0.4 0.4*0.4=0.16 3 1.6 1.4 1.96 0 1.6 -1.6 2.56 1 1.6 -0.6 0.36 2 1.6 0.4 0.16 Σ 5.20 n-1= 5-1= 4 5.20/4 = 1.3 square root SD = 1.14 Standard Error Mean (SEM) = SD/n Square root = 0.51
