Stat 321 Fall 2004 Exam 2 Preparation

• Tuesday, October 26, 1:10-2:00
• Covers chapter 3 and sections 1 and 2 of chapter 4, handouts from days 11-20, investigations 7-11, suggested homework problems from weeks 3-5
• You may use book, handouts, two other sheets of notes
• Technology
• Bring calculator
• No use of Minitab
• Minitab and/or applet output may be included
• Interpretations, explanations as important as calculations
• Comparable to in-class, investigation, homework questions

Big Ideas

• Random variables
• Discrete
• Probability mass function (pmf)
• Reports possibilities and probabilities
• Non-negative, sums to one
• Cumulative distribution function (cdf)
• Reports probability of being less than or equal to input value
• Domain: all real numbers
• Non-decreasing, approaches 0 at low end, approaches 1 at high end
• Expected value
• Calculation
• Interpretation: long-term average value
• Of function of random variable
• Rules
• E(aX+b)=aE(X)+b
• E[h(X)] does not necessarily equal h[E(X)]
• Variance, standard deviation
• Common families of distributions
• Binomial
• Conditions
• Number of successes in fixed number of trials
• Pmf
• Parameters n, p
• Expected value, variance
• Calculations with Minitab
• Tests, p-values
• Hypergeometric
• Number of successes when sampling without replacement
• Pmf
• Parameters N, M, n
• Expected value, variance
• Binomial approximation
• Geometric
• Number of failures before first success
• Pmf
• Parameter p
• Expected value, variance
• Estimating parameter from data
• Negative binomial
• Number of failures before rth success
• Pmf
• Parameters r, p
• Expected value, variance
• Poisson
• Pmf
• Parameter lambda
• Expected value, variance
• Estimating parameter from data
• Continuous probability distributions
• Probability density function (pdf)
• Non-negative, integrates to one
• Cumulative distribution function (cdf)
• Calculating probabilities
• From pdf
• Geometry, integration
• From cdf
• Expected value, variance
• Percentiles (including median)
• Uniform distribution

Some Advice

• Be prepared to think/explain/interpret
• Do not just plug into formulas from text
• Organize note sheet for efficient retrieval of information
• Don’t plan to use text, handouts too much
• Prepare as if exam were closed book/notes
• Understand, don’t memorize
• Time may be a concern
• Take advantage of partial information provided
• Don’t waste time re-calculating what’s already given
• Re-read
• Handouts
• Especially expository passages, “boxed” paragraphs
• Chapter from text
• Review problems
• Re-work examples from handouts
• Re-work investigations
• Work suggested homework problems
• Re-work examples from text
• Work additional exercises from text