Quiz2S08_Answers

Quiz2S08_Answers - and the standard deviation is 2 You know...

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James Abbey Stat 226 Section C Spring 2008 -- Quiz # 2 NAME: . Data Set: 2, 3, 4, 5, 5, 5, 6, 6 1. Find the following: a. Mean 36/8 = 4.5 . b. 5-Number-Summary M=(n+1)/2 = (8+1)/2 = 4.5 position 4.5 Median is 5 Q1: Data to the LEFT of the median 2, 3, 4, 5 M=(n+1)/2 = (4+1)/2 = 2.5 th position (3+4)/4 = 3.5 Q3: Data to the RIGHT of the median 5, 5, 6, 6 M=(n+1)/2 = (4+1)/2 = 2.5 th position (5+6)/2 = 5.5 NOTICE THAT JMP USES A DIFFERENT FORMULA for the 25%-tile and 75%-tile. Min Q1 Q2 = Median Q3 Max 2 3.5 5 5.5 6 2. [ NOT GRADED] Suppose you are told the mean of a certain distribution is 10
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Unformatted text preview: and the standard deviation is 2. You know that that distribution is normal. You observe an x-value of 6. Find the z-score for the observed x=6. Is the value unusual? EXPLAIN! σ μ-= x z = 2 10 6-= 2 4-= -2.0 Apply 68-95-99.7 or z-table. Look for value as or more extreme. z-table area lower than -2 is 0.0228 or 2.28%. By 68-95-99.7, you would find the area is 2.5% or 0.025. Thus, the value does seem somewhat unusual....
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This note was uploaded on 05/05/2010 for the course STAT 226 taught by Professor Abbey during the Fall '08 term at Iowa State.

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