Review for Exam 2 (Ch.6,7,8,12) Ch. 6 Sampling Distribution Despite interest in population mean (µ), most of the time we only study a sample  sample mean (x). Central Limit Theorem - IF the population has mean  and variance 2, and the sample size n is large enough, THEN: the sample mean x follows a normal distribution BUS304 – Chapters 6, 7, 8,12

Ch. 7 Estimating Population Mean The confidence interval for population mean using sample data: when population variance known when population variance unknown Determining sample size (pilot sample) BUS304 – Chapters 6, 7, 8,12

Ch. 8 Hypothesis Tests Hypothesis Tests are set of methods and procedure to study the reliability of claims about population parameters The mean price of a beach house in Carlsbad is at least $1million dollars One tail (Upper / Lower), Two Tail Example of Upper Tail test, population variance known (else use t distribution) H0: μ ≥ $1million HA: μ < $1million H0: μ ≤ 3 HA: μ > 3 Reject when the sample mean is too high z Decision rule If zx > z, reject H0 If zx ≤ z, do not reject H0 BUS304 – Chapters 6, 7, 8,12

Ch. 12 Correlation & Regression Examine the relationship among two or more random variables Correlation (r) The value will be from -1 to 1, Measures the degree of linearity H0 :  ≥ 0, HA:  < 0 If t < t, reject the hypothesis H0, If t ≥ t, do not reject the hypothesis H0. Regression Model x (independent), y (dependent) variables, R2=r2 measure of goodness of fit Positive Relation yi = 0 + 1 * xi + i BUS304 – Chapters 6, 7, 8,12