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Quiz2Sols

# Quiz2Sols - ssq height =(3^2 71^2*30(3^2 62^2*40 = 151500...

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Stat 21 Quiz 2 Solutions, Spring 2010 1) a) bar(x) = 2, bar(y) = 3.4 sd(x) = 2, sd(y) = 4.63, r = .60 b) 5, symmetric over line x = 3 c) not possible, no straight line possible between points (1,1), (2,5), (3,3), (5,1). 2)a) SU(X) = 2 SU(Y) = .5(2) = 1 Y = 70 + 1(8) = 78 b) SU(Y) = 1.30 (1.25 is close) SU(X) = 1.30(.5) = .65 X = 12+3(.65) = 13.95 3) avg height = (71(30)+62(40))/70 = 65.86 avg weight = (200*30+140*40)/70 = 165.71
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Unformatted text preview: ssq height = (3^2+71^2)*30 + (3^2+62^2)*40 = 151500 + 154120 = 305620 ssq weight = (20^2 +200^2)*(30)+(20^2 +140^2)*40 = 1212000 + 80000 = 2012000 man sum(xy) = (.6*(20)*3+200*71)*30 = 427080 woman sum(xy) = (.5*(20)*3+140*62)*40 = 348400 tot sum(xy) = 775480 r = (1/70*(775480) - 65.86*(165.71))/(sqrt(305620/70 - 65.86^2)*sqrt(2012000/70-165.71^2)) = (1/70*(775480) - 65.86*(165.71))/(5.37*35.80) = .86...
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