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Chapter 9 Key Ideas and Words Section 9.1 ο· Point estimate o statistics vs. parameter π₯ o point estimate for population proportion p is Μπ = π o p may also represent a probability of a binomial distribution, such as p=0.5 for a fair coin. ο· Confidence interval for an unknown parameter ο· Margin of error ο· Interpretation of what is meant by being β95%β confident (think simulations ο· Formula for confidence interval for population proportion, p. ο· Know z-multipliers for 90%, 95%, and 99% confidence intervals. ο· Requirements: Minimum sample size and sample size very small relative to population size. o np(1-p) >= 10 o n <= 0.05N, N=population size ο· Calculating sample size to obtained desired margin of error E. o Using educated guess for population proportion. o Using p=0.5 for conservative (large) sample size. o Round up to nearest integer. Section 9.2 ο· Point estimate for population mean is the sample mean ο· Distribution of z-score for sample mean using sample standard deviation, S, instead of population standard deviation, π. ο· Studentβs t-distribution o Degrees-of-freedom o t-table ο· t-distribution vs. standard normal (Z) distribution ο· Formula for confidence interval for population mean π ο· How to calculate approximate sample size to get desired margin of error E. o Note: This calculated n is likely too small because z-value < t-value