A researcher wants to construct a 99% confidence interval fo…
A researcher wants to construct a 99% confidence interval for the proportion of elementary school students in Seward County who receive free or reduced-price school lunches. What sample size is needed so that the confidence interval will have a margin of error of 0.07?
Read DetailsSix measurements were made of the magnesium ion concentratio…
Six measurements were made of the magnesium ion concentration (in parts per million, or ppm) in a city’s municipal water supply, with the following results. It is reasonable to assume that the population is approximately normal. Based on a 98% confidence interval for the mean magnesium ion concentration, is it reasonable to believe that the mean magnesium ion concentration may be greater than 195? (Hint: you should first calculate the 98% confidence interval for the mean magnesium ion concentration.)
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