Lecture_14 (short)

# Dev 1 2 condence interval for dierence between means

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Unformatted text preview: ill Motors Independent Sample Rafael Mendoza Elementary Business Statistics – Class 14 McCombs Independent Samples, Unequal Population Standard Deviations Case Unequal Population Std. Dev. σ1 ￿= σ2 Conﬁdence Interval for Diﬀerence Between Means: ¯ ¯ ¯ ¯ X1 − X2 ± t∗ × Standard Error for (X1 − X2 ) ¯ ¯ Standard Error: for (X1 − X2 ) = ￿ s2 1 n1 + s2 2 n2 Degrees of freedom: - complicated Use StatTools to calculate the conﬁdence interval Example: Customer waiting at R&P Supermarket Rafael Mendoza Elementary Business Statistics – Class 14 McCombs Tests of Signiﬁcance the return to the Normal Distribution: the population standard deviation, σ , is known Rafael Mendoza Elementary Business Statistics – Class 14 McCombs Statistical Inference Methods for drawing conclusions about a population from sample data are called statistical inference. Methods 1 2 Conﬁdence Intervals - estimating a value of a population parameter Tests of signiﬁcance - assess evidence for a claim about a population Inference is appropriate when data are produced by either a random sample or a randomized experiment Rafael Mendoza Elementary Business...
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## This document was uploaded on 02/19/2014 for the course STA 309 at University of Texas at Austin.

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