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Space for Questions
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MATH 141
Day 23
Lecture Notes
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Exam 3 Thursday, November 20
At this point, you know what to expect. Doors open around 7:45 AM
Have calculator memory (not just RAM) cleared.
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As you probably recognize from the exam review you've done,
the hardest material on the exam is from Chapter 7 and Section 8­4.
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(Can also use binompdf, which we will discuss in a minute.)
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where November 18, 2014
trials = number of trials in the binomial experiment
probability = probability of success
value = number of successes you want
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Two useful calculator functions (TI­83):
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We will actually use the calculator here. Formula: 14
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n = number of trials
p = probability of success
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Two useful calculator functions (TI­83):
1. binompdf(trials, probability, value)
where trials = number of trials in the binomial experiment
probability = probability of success
value = number of successes you want
gives the probability of having exactly x successes in n trials. 2. binomcdf(trials, probability, value) gives the probability of having at most
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A light bulb company knows from its research that each lightbulb it produces has a probability of approximately 0.92 of being good. It is also known that the defectiveness of one lightbulb does not change the probability that any others are defective. In a shipment of 100, find the probability that...
...at most 90 are good.
...at least 90 are good.
...between 85 and 95 are good. 19
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We want a number to say how much more "spread out" B is. 21
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Expected Value vs. Expected Net Gain
A man buys a one­year life insurance policy for $100. If he dies during the year, his family will get $25,000.
What is the expected value of the policy for the insurance company?
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What you need to know about Variance and Standard Deviation:
1. they measure how "spread out" the variable is.
2. they can be calculated in a calculator or computer (and how to calculate them in a calculator or computer)
3. Variance = (Standard Deviation)
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Go to STAT: Edit
Put entries for list in L1. Can use Mean, Median, StdDev commands. Newer calculators:
Put entries for random variable in L1,
put probabilities corresponding to these values in L2.
Then use STAT:Calc:1­Var Stats. 28
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Box A contains four white marbles and five black marbles. Box B contains three white marbles and six black marbles. An experiment consists of first selecting a marble at random from Box A. The marble is transferred to Box B and then a second marble is drawn from Box B. What is the probability that the first marble was white given that the second marble was white?
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