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Unformatted text preview: Statistics 200 B1 Exam 1 3/04/2010 Name:________ Solutions ___________________ NetID: __________________________________ There are 6 problems and a bonus problem. Each problem is worth the same total number of points. Here are a few formulas and expressions as reminders: - -- = ∑ y i x i s y y s x x n r 1 1 x y s s r b = 1 x b y b 1- = ) ( ) ( ) ( ) ( B and A P B P A P B or A P- + = ) | ( ) ( ) ( A B P A P B and A P = ∑- =- = = 2 2 2 ) ( ] ) [( ) ( X k k X X x p X E X Variance μ μ σ Y X Y X Y X σ ρσ σ σ σ 2 2 2 2 + + = + n σ ) 1 ( p np- n p p ) 1 (- m x ± 1. Data on 12 large US cities include population (in thousands) and open space (acres of park and undeveloped space). For each city the ratio of open space to population (acres per 1000 people) was computed. The sorted ratios are as follows: 3.67 4.02 6.23 6.25 7.04 7.61 8.07 8.26 9.30 13.12 14.87 The mean is 8.04 and the standard deviation is 3.42. a) Find the five number summary for these data. min=3.67 Q1=6.23 median=7.61 Q3=9.30 max=14.87 b) Compute the interquartile range. IQR = Q3 – Q1 = 9.30 – 6.23 = 3.07 c) Which, if any values are outliers more than 1.5*IQR above Q 3 or more than 1.5*IQR below Q 1 ? lower outlier screen: Q1 – 1.5*IQR = 6.23 – 4.605 = 1.63 - no low outliers upper outlier screen: Q3 + 1.5*IQR = 9.30 + 4.605 = 13.9 – one high outlier: 14.87 d) Find the largest and smallest z-values (standardized values) in the data. d) Find the largest and smallest z-values (standardized values) in the data....
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This note was uploaded on 09/11/2011 for the course STAT 200 taught by Professor Agniel during the Spring '09 term at University of Illinois at Urbana–Champaign.
- Spring '09