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 1. Discrete Variables 
 Binomial 
 Poisson 
 2. Normal 
 Normal 
 Inverse Normal' 
 3. Approximation to Normal 
 Binomial 
 Poisson 
Distributions
Discrete Variables Normal Approximation to Normal
1. Discrete Variables
Binomial
Conditions
Trial Have 2 outcomes
Fixed # of trials
Outcomes each trial are independent
Probability (Success) same each trial
Discrete Variables
Formulas
Probability
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Mean
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Variance
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Standard Deviation
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Poisson
Conditions
Events
cannot occur simultaneously
occur at random
are unpredictable
Each occurrence is independent
Prob(event) is proportional size of interval
Formulas
Probability
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Mean
• λ
Discrete Variables
Continuity Correction
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Normal
Gaussian Function
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Standard Deviation
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68%
95%
99.7%
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Standardize
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Inverse Normal'
Step 1
N(3,4) and P(0<x)=0.41
Step 2
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Step 3
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Step 4
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P(0<z)=0.41 -> z=1.34
Step 5
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3. Approximation to Normal
Binomial
When
• np>5 and nq >5
Use
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Poisson
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When
• λ>20
Use
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