MATH 2510 Chapter Notes - Chapter 6: Standard Score, Standard Deviation, Sampling Distribution
9 Nov 2018
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Control charts- x axis is observations, y axis is the data. Lines go horizontally across the graph at the mean, and +- 2 standard deviations, and +- 3 standard deviations. 1 point is lies outside of +- 3 stand dev. 9 points in a row lie on the same side below or above the mean. 2 out of three consecutive points lie beyond the +- 2 stand dev line. Z score- aka standard score is z = (x - mean)/standard deviation. Z score is the number of standard deviations above or below the mean. A standard normal distribution is when all the x values are converted to their respective z scores and then plotted like a normal distribution curve with the mean = 0 and each standard dev = +-1. Standard error is the standard deviation of a sampling distribution. Se = stand dev/sqrt(n) z=(xbar - miu)/(stand dev/sqrt(n)) N (the number of samples) is greater than or equal to 30.
