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Finding Critical Values In constructing confidence intervals for σ or σ2, Table A-4 can be used to find the critical values
where k is the number of degrees of freedom and zα/2 critical z score described in Section 7-1. Use this approximation to find the critical values
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Student's Solutions Manual To Accompany Elementary Statistics Tenth Edition
- Use the t-distribution to find a confidence interval for a difference in means μ1-μ2 given the relevant sample results. Give the best estimate for μ1-μ2, the margin of error, and the confidence interval. Assume the results come from random samples from populations that are approximately normally distributed.A 90% confidence interval for μ1-μ2 using the sample results x¯1=8.6, s1=2.7, n1=50 and x¯2=13.7, s2=5.8, n2=50Enter the exact answer for the best estimate and round your answers for the margin of error and the confidence interval to two decimal places. *Additional info that may be helpful: When choosing random samples of size n1 and n2 from populations with means μ1 and μ2, respectively, the distribution of the differences in the two sample means, x¯1-x¯2, has the following characteristics.Center: The mean is equal to the difference in population means, μ1-μ2.Spread: The standard error is estimated using SE=s12n1+s22n2.Shape: The standardized differences in sample means follow a…arrow_forward(points) Suppose a 95% confidence interval for m turns out to be (1,000, 2,100). Give a definition of what it means tobe "95% confident". A. In repeated sampling, 95% of the intervals constructed would contain the population mean. B. 95% of the observations in the sample fall in the given interval. C. 95% of the observations in the entire population fall in the given interval. D. In repeated sampling, the population parameter would fall in the given interval 95% of the time.arrow_forwardthe given information to find the number of degrees of freedom, the critical values χ2L and χ2R, and the confidence interval estimate of σ. It is reasonable to assume that a simple random sample has been selected from a population with a normal distribution. White Blood Counts of Women 80% confidence; n=150, s=1.95 (1000 cells/μL)arrow_forward
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