5.3. Connecting the Standard Deviation and Normal Distribution http://www.ck12.org
(c)
99 .7% − 95%= 4 .7%
x
x
All plants plants with
within 3σ heights greater
from mean. than 10.9 cm
4 .7%
2= 2 .35%
331 × 0. 0235 =8 plantsTherefore, eight plants in the greenhouse would be shorter than 10.9 cm.
TABLE5.4:
x (x−x ̄) (x−x ̄)^2
175 -7 49
179 -3 9
179 -3 9
181 -1 1
183 1 1
183 1 1
184 2 4
184 2 4
185 3 9
187 5 25
Sum = 1820 112x ̄=1820
10
σ=√
∑(x−x ̄)^2
n
σ=√
112
10
σ=√
11. 2
x ̄= 182 σ= 3. 35(a)
(b)
95% of students= 0. 95 ×325 students=308 students