Exam 1 Cheat Sheet

# Exam 1 Cheat Sheet - Frequency Distribution(Example Key...

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Frequency Distribution (Example) Key values: Minimum value- 0 Maximum value- 150 Task: Create distribution table using #6 of classes Minimum Class Width High Value-Low Value [ Minimum is always the next highest whole number ] # Of classes (150-0) / 6 = 25 Minimum Class Width: 25 +1= 26 Determine Class Limits (Highs and Lows) Steps Start with lower limits Start with the minimum value and add the class width -Here (0, 26, 52, 78, 104, 130) Upper limits are determined by: High Value-Low Value # Of classes Measures of Variation Population Variance: the sum of the squares of the deviations, divided by N σ = Σ ( × - μ ) Ν Population Standard Deviation: the (sum of x values/# of values) – population mean σ = Σ ( × ) - μ Ν Sample Variance: divide the sum of the squared distance by n-1 s = Σ ( × - χ ) n-1 Sample Standard Deviation: square root of the sample variance s = √Σ ( × ) - ( Σ × ) n n-1 Chebychev’s Theorem For any distribution, the portion of data lying within k standard deviations (k>1) of the mean is at least 1-1/k Standard Deviations At Least 2 1-1/2 = 3/4 3 1-1/3 = 8/9 4 1-1/4 = 15/16 Example: Given a distribution with a mean of 50 and a standard deviation of 6. According to Chebychev’s

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Exam 1 Cheat Sheet - Frequency Distribution(Example Key...

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