Ivo Dinov UCLA Statistics, Neurology, LONI, UCLA Statistics 

STAT 13 (1a, 1b, 1c) 
Introduction to Statistical Methods for the Life and Health Science 
Department of Statistics 
Instructor: Ivo Dinov 
Homework 5 
Due Date: Friday, Nov. 19, 2004 
x  $5  $5  $10  $60 
pr(X=x)  0.581  0.346  0.064  0.009 
 What are the values of E[X_bar] and SE[X_bar]?
 What is the approximate distribution of X_bar? What theorem was needed to decide this?
 Calculate the probability of, on average, making a positive return from placing one hundred separate bets with $5 stakes.
 Repeat the calculations above using 1,000, 5,000 and 10,000 bets.
 Create a scatter plot of probability that the mean return from playing Tai Sai is positive (on yaxis) versus number of bets (on xaxis). Comment on what the plot appears to show.
Sexual Content Ads 
n_{1}=40 
X_{1}_bar=6.9 
S_{1}=1.87 
General Audience Ads 
n_{2}=58 
X_{2}_bar=5.1 
S_{2}=1.51 
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