Question

1.) As part of an environmental studies class project, students measured the circumferences of a random sample of 45 blue spruce trees near Brainard Lake, Colorado. The sample mean circumference was x bar = 29.8 inches. Assume that s is known to be 7.2 inches. Find a 99% confidence interval for the population mean circumference of all blue spruce trees near this lake.

2.) A pizza shop owner wishes to find the 90% confidence interval of the true mean cost of a large plain pizza. How large should the sample be if she wishes to be accurate to within $0.15? The standard deviation of the population is approximately $0.26

Answer 1

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