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A study of 36 marathon runners showed that they could run at an average rate of 7.8 miles per hour. The sample standard deviation is 0.6. Find a point estimate of the population mean. Find the 90% confidence interval forthe mean of all runners. Based on the results, what minimum speed should a runner obtain to qualify to run in a marathon? answer

  • statistics -

    Z = (score-mean)/SEm

    SEm = SD/√n

    90% = mean ± 1.645 SEm

    What is your cutoff point to run?

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