Question

Suppose a landscaper wants to tell his clients the average length of the blades of grass in a freshly mowed lawn. He measures the length of 50 randomly selected blades of grass immediately after mowing a lawn. He does not know the population standard deviation of grass lengths in the lawn, but his data are normally distributed with no outliers. The table contains a summary of his data.

Sample size	Sample mean (cm)	Sample standard deviation (cm)
?n	?⎯⎯⎯x¯	?s
50	4.12576	0.89526

Calculate the margin of error, ?m, for a 95% ?t‑confidence interval for a population mean. Then, compute the upper and lower limits for the confidence interval. Give each of your answers with three decimal places of precision.

?=

lower limit = cm

upper limit = cm

Answer 1