Answer:
Therefore the number of standard deviation is 1.41 ft.
Explanation:
Mean: The average of all numbers is known as mean.

To find out the number of standard deviation,
- First we have find out the mean of the distribution.
- Then subtract mean from each number.
- Squares of the difference.
- Mean of the squares.
- square root of the mean.
Given mean of the orchard tree is 11.8.
Given distribution is 12.5 ft, 9.8 ft, 13.5 ft,11.2 ft, 12.3 ft , 14.2 ft, 11.7 ft, 9.8 ft , 12.6 ft, 10.4 ft.
In order to get the number of standard deviation, we have to subtract mean from each number .
Then (12.5-11.8)ft,(9.8-11.8)ft , (13.5-11.8)ft,(11.2-11.8) ft, (12.3-11.8) ft , (14.2 -11.8)ft, (11.7 -11.8)ft,( 9.8-11.8) ft , (12.6-11.8) ft,( 10.4-11.8) ft.
=0.7 ft, -2.0 ft,1.7 ft, -0.6 ft,0.5 ft,2.4 ft, -0.1 ft , -2.0 ft,0.8 ft,-1.2 ft
Therefore the number of deviation is


= 1.4085
≈1.41
Therefore the number of standard deviation is 1.41 ft.