Quiz 6 Solutions

Quiz 6 Solutions - BA 240 Show your work Completely Round...

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BA 240 W. Li Answer Sheet 1 QUIZ 6 Solution Show your work Completely Round to the THIRD decimal place. Interpret your results! Problem 1 : Suppose the average annual expense for a random sample of 12 stock funds is normally distributed with mean of 1.63 percent with a standard deviation of .31 percent. Calculate a 95 percent confidence interval for the mean annual expense charged by all stock funds. Note: “the mean annual expense” indicates this question is asking for POPULATION MEAN ; “random sample of 12 stock funds” indicates this is a SMALL SAMPLE therefore we should use t test statistic . 12 n , 63 . 1 x , 31 . 0 s , 05 . 0 95 . 0 1 , 11 1 n df , 201 . 2 11 , 025 . 0 t 827 . 1 , 433 . 1 197 . 0 63 . 1 12 31 . 0 201 . 2 63 . 1 2 / n s t x 201 . 2 2 / t Lower Limit = 1.433 Upper Limit = 1.827 The 95% confidence interval for the mean annual expense charged by all stock funds is between 1.433 percent and 1.827 percent (or 1.433% and 1.827%).
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This note was uploaded on 05/15/2011 for the course BA 240 taught by Professor Li during the Spring '08 term at Bellevue College.

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Quiz 6 Solutions - BA 240 Show your work Completely Round...

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