cheating sheet-quiz2

# cheating sheet-quiz2 - Confidence Intervals Large Sample...

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Confidence Intervals Large Sample CIs for the Mean x ± z α / 2 σ n (n 30) •If σ is unknown and the sample size is large (n 30), use sample standard deviation s . x ± z / 2 s n Small Sample CIs for Mean x ± t / 2 s n *area of α /2 under t curve having n – 1 degrees of freedom (df). •Effect of df on t-distribution x ± t 0.025 s n = 1.3433 ± 2.145 0.1921 15 = 1.3433 ± 0.1064 = [1.2369, 1.4497] Small Sample CI: Debt to Equity Ratio As the number of degrees of freedom increases, spread of t  distribution decreases and the t curve approaches the standard  normal curve.   n = z α / 2 σ B 2 A sample size CI for Population Proportions If the sample size n is large , then a (1 - a)100% confidence interval for p is ( 29 n p p z p ˆ 1 ˆ ˆ 2 - ±   n = p ( 1 - p ) z α / 2 B 2 Memo Hypothesis Testing Selecting Appropriate CI Null and Alternative Hypotheses Null hypothesis

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## This note was uploaded on 03/31/2008 for the course BUAD 310 taught by Professor Lv during the Spring '07 term at USC.

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cheating sheet-quiz2 - Confidence Intervals Large Sample...

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