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Chapter_6

# Thesamplemeancanbecalculatedusing

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Unformatted text preview: spent the amount of money found in the interval from part (a)? Explain your answer. c) What is the margin of error for the 90% confidence interval? d) How many students should you sample if you want a margin of error of \$5 for a 90% confidence interval? 4 EXAMPLE 2: A sample of 12 STAT 301 students yields the following Exam 1 scores: 78 62 99 85 94 53 88 90 86 92 75 92 Assume that the population standard deviation is 10. The sample mean can be calculated using SPSS or calculator to be 82.83. (Note: Do NOT use any SPSS confidence intervals—they are good only for Chapter 7, not this type of CI. You must get these Z confidence intervals by hand.) a) Find the 90% confidence interval for the mean score for STAT 301 students. b) Find the 95% confidence interval. c) Find the 99% confidence interval. d) How do the margins of error in (b), (c), and (d) change as the confidence level increases? Why? 5 Section 6.2: Hypothesis Testing The 4 steps common to all tests of significance: 1. State the null hypothesis H0 and the alternative hy...
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