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Test 2 Review Vocabulary and symbolic notation: Point estimate of the population mean of a statistic used to estimate the value of a parameter. Confidence interval- is an interval of numbers obtained from a point estimate and a percentage that specifies how confident we are that a parameter lies in an interval. Confidence level-confidence percentage Margin of Error (E) T-distribution, degrees of freedom Assumptions for Confidence Intervals: Point estimate of the population mean value of a statistic used to estimate the parameter. Normal populations or large samples. All samples are simple random samples Chapter 6 Know the properties of the normal and standard normal curves Center at Symmetry Area under the curve is 1 Most area within 3 standard deviations about the mean Bell shaped Know how to convert from a normal variable to a standard normal variable. x- z Know the 68.26-99.54-99.74 Rule Know how to find the areas under the standard normal and normal curve using tables and using symmetry. Know how to find x variable for a given probability or percentage. Know how to construct a normal probability plot. Know how to determine if data is normally distributed. Chapter 7 Know what is the sampling distribution of the sample mean X , know the mean and standard deviation of X , x and x . Know how the shape of the distribution changes with increasing sampling size n. When X has normal distribution, when approximately normal distribution. Know the central limit theorem. Find probabilities using the sampling distribution of X . Chapter 8 Know that X is a point estimate of Know how to compute (1 ) 100% Confidence Interval for 1. When is known (Z-interval) 2. When is unknown (T-interval) Interpret the Confidence Interval What is the margin of error for a given, CI, know how it changes with increased sample size. Also know how the confidence level affects the Confidence Interval. Estimate the sample size for given E and confidence level. Chapter 9 Know new vocabulary and symbolic notation: Null and alternative hypotheses Two - tailed, left-tailed, right-tailed alternative hypothesis Type I and II errors