Question

You are reading an old report about tree heights in a certain area.  The report states (without stating the confidence level) that the true population mean tree height lies between 25.5 m and 29.1 m. The sample size is given as 38 trees, and the document states that the population standard deviation is assumed to be 5.1 m.  You wish to determine what confidence level was used to find this confidence interval. What was the sample mean found in the study?       What was the margin of error used in the confidence interval?      What confidence level would this critical value correspond to?  Give your answer in %, rounded your answer to the nearest whole percent (for example, if the answer is 91.5, enter 92). Do not include the % symbol in your answer.

Answer 1

Answert la) Sample mean Copper limit + lower limit) 2 (25.5 +79.1) 2 27.3 (6) Margin of erra F: upper limit - x 25.5 - 27.3 -1.8 (standard deviation = 5.1 n = 38 margin of cardi Zx S Jū Z Ja - -1.8% Jua Sil : -2.28 (d) 2 = -2.28 0.97 2:1-0.0302 : 977.