Question 560948: Following a brushfire, a forester takes core samples from the ten surviving Bigcone Douglas-fir trees in a test plot within the burn area, and a dendrochronologist determines the age of the source trees to be as follows (in years):
15 38 48 67 81 83 94 102 135 167
3. Calculate the sample mean and standard deviation for the age of Bigcone Douglas-fir trees based on the data above. If this accurately represents the population mean and standard deviation for the age of surviving Bigcone Douglas-fir trees in the burn area, what is the probability that a randomly selected surviving Bigcone Douglas-fir tree from the burn area will be 111 years old or less? Round to the nearest hundredth
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Following a brushfire, a forester takes core samples from the ten surviving Bigcone Douglas-fir trees in a test plot within the burn area, and a dendrochronologist determines the age of the source trees to be as follows (in years):
15 38 48 67 81 83 94 102 135 167
3. Calculate the sample mean and standard deviation for the age of Bigcone Douglas-fir trees based on the data above.
sample mean = 83 years
sample std = 45.19 years
----------------------------------
If this accurately represents the population mean and standard deviation for the age of surviving Bigcone Douglas-fir trees in the burn area, what is the probability that a randomly selected surviving Bigcone Douglas-fir tree from the burn area will be 111 years old or less? Round to the nearest hundredth
------
z(111) = (111-83)/45.19 = 0.6196
------
P(x <= 111) = P(z <= 0.6196) = 0.7322
=======================================
Cheers,
Stan H.
================
|
|
|
