# exam3Sp10 - Exam 3 Spring 2010 1 Name_ Psych Stats Spring...

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Exam 3 Spring 2010 Name_________________________ Psych Stats Spring 2010 Brannick Exam 3 Instructions: Write your name and U number on the scantron. Answer any 40 of 45 questions on the exam by bubbling in the best of the four alternatives given. For those questions you wish to omit, bubble in “e.” If you answer all 45, I will choose the last 5 for you, so it is in your interest to pick 5 and bubble in “e”. You can take the printed exam with you when you finish, but turn in the scantron. Handy formulas: 2 1 2 1 2 2 X X X X S S S + = - N s s X X 2 = ; 1 ) ( 2 2 - - = N X X s X pairs D pairs D D N S N SD S 2 = = t X X S X X = - - 1 2 1 2 t X S X = - μ D S D t - = N z z r Y X = ; X X S X X z - = X Y S S r b = ; X b Y a - = ; bX a Y + = ˆ - = 2 ) ( G i tot X X SS SS tot =SS b +SS w 2 ) ( A i w X X SS - = 2 ) ( G A g b X X N SS - = MS =SS/df; Df tot = df w +df b; df t = N-1; df w = N-k; df b = k-1 A W N MS q HSD α = W B obt MS MS F = Critical values of t , alpha = .05, two-tails Df T Df t 1 12.706 6 2.447 2 4.303 7 2.365 3 3.182 8 2.306 4 2.776 9 2.262 5 2.571 10 2.228 1

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Exam 3 Spring 2010 Critical values of F Numerator df: df B df W 1 2 3 4 5 5 5% 1% 6.61 16.3 5.79 13.3 5.41 12.1 5.19 11.4 5.05 11.0 10 5% 1% 4.96 10.0 4.10 7.56 3.71 6.55 3.48 5.99 3.33 5.64 12 5% 1% 4.75 9.33 3.89 6.94 3.49 5.95 3.26 5.41 3.11 5.06 14 5% 1% 4.60 8.86 3.74 6.51 3.34 5.56 3.11 5.04 2.96 4.70 2
Exam 3 Spring 2010 Chapter 9 Two-Sample t -Test 1.We want to know if a new software product helps people pick stocks. We randomly assign students in a finance class to either get the new software or to get the software in use for the last 10 years. Each student gets bogus money at the beginning of class; they get to buy and sell stock over the course of the semester, and the profit/loss for each student is calculated at the end of the class. We compute the mean profit for each group. The data should be analyzed using a _______ t -test. a. Independent b. Paired (dependent) c. Participant d. Two-sample 2.In the above study (financial software), what would be the null hypothesis? a. 2 1 μ < b. 2 1 σ c. 2 1 = d. 2 1 3. For the above study (financial software), what formula should we use? a. t X S X = - b. D S D t - = c. t X X S X X = - - 1 2 1 2 d. W B obt MS MS F = 4.Homogeneity of variance means _______. a. Population means for the groups are the same b. Population variances for the groups are the same c. Sample sizes for the groups are the same d. Sample variances for the groups are the same 3

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Exam 3 Spring 2010 5. Suppose we have two groups with means 1 μ and 2 , the null hypothesis is true, and alpha is .05. What percent of the time will t obt fall in the rejection region? a.
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## This note was uploaded on 05/21/2011 for the course PSY 3204 taught by Professor Brannick during the Spring '10 term at University of South Florida - Tampa.

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exam3Sp10 - Exam 3 Spring 2010 1 Name_ Psych Stats Spring...

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