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Unformatted text preview: Stat 104, Section 4 Handout Solutions Benny, Thursday, 4:00pm, SC 309 Key concepts • Random Variables (discrete vs. cont., expectations, means, variances, etc.) • Join and conditional probability distributions (for discrete Random Variables) • Binomial random variables • Poisson Random Variables Practice Problems 1. Harvard College is composed of 52% women. There are 275 students in Stat 104, of which 115 are women. All of the following can be done using a computer tool such as Mathematica or the URL below. http://dostat.stat.sc.edu/prototype/calculators/index.php3?dist=Binomial a. Say there are 21 students in this section, and 14 of them are women. What is the probability of selecting 14 women from 21 students from Harvard? P ( X = 14) = 21 14 . 52 14 (1 . 52) 21 14 = . 0722 b. What is the expected number of women from a simple random sample of 275 Harvard students? What is the standard deviation? μ x = np = 275(0 . 52) = 143 σ x = p np (1 p ) = p 275(0 . 52)(0 . 28) = 8 . 285 c. What is the probability of selecting exactly 115 women in a sample of 275 students from...
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This note was uploaded on 03/27/2012 for the course STATS 104 taught by Professor Michaelparzen during the Fall '11 term at Harvard.
 Fall '11
 MichaelParzen
 Binomial, Conditional Probability, Probability, Variance

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