Answer:
9 inches
Step-by-step explanation:
The population is within 6 standard deviations of the mean with a confidence of 99.7 percent, 3 above and 3 below
The standard deviation of the sample mean is equal to the population standard deviation divided by the square root of the sample size
population standard deviation = 36
sample size = 144
standard deviation of the sample mean = 36/ sqrt(144)
=36/12
=3
The margin of error is the number of standard deviations above the mean * the standard deviations
margin of error = 3 * 3
= 9 inches
