The diameter of the stem of a wheat plant is an important trait because of its relationship to breakage of the stem. An agronomist measured stem diameter in eight plants of a particular type of wheat. The mean of these data is 2.275 and the standard deviation is 0.238. Construct a 80% confidence interval for the population mean.

7.79771≤x≤8.20229  

Step-by-step explanation:  

Given the following  

sample size n = 8  

standard deviation s = 0.238  

Sample mean = 2.275  

z-score at 980% = 1.282

Confidence Interval = x ± z×s/√n  

Confidence Interval = 8 ± 1.282×0.238/1.5083)  

Confidence Interval = 8 ± (1.282×0.15779)

Confidence Interval = 8 ±0.20229    

CI = {8-0.20229, 8+0.20229}  

CI = {7.79771, 8.20229}

Hence the required confidence interval is 7.79771≤x≤8.20229

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step-by-step explanation: