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ASK THE PROFESSOR FORUM

Course Documents

Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples

Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

Ask the Professor Forum

I am also having trouble solving this problem: A batch consists of 12 defective coils and 88 good ones. Find the probability of getting two defective coils when two coils are randomly selected if the first selection is replaced before the second is made.

Posted to STATS 1 on Monday, August 19, 2013   Replies: 1


Professor Mcguckian
08/19/2013
5:10 PM EST

Hi Gail,
Here is how to solve this one:
P(2 defects) = P(1st is defective) * P(2nd is defective) = # of defective coils/total * # of defective coils /total = 12/100 * 12/100 = 144/10,000 = 0.01444

Hope that helps!

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