Answer:
Step-by-step explanation:
we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = variable
µ = mean output
σ = standard deviation
From the information given,
µ = 14
σ = 3
1) P(x < 20)
For x = 20,
z = (20 - 14)/3 = 2
From the normal distribution table, the corresponding probability value is 0.98
% = 0.98 × 100 = 98%
2) P(11 ≤ x ≤ 17)
For x = 11,
z = (11 - 14)/3 = - 1
From the normal distribution table, the corresponding probability value is 0.16
For x = 17,
z = (17 - 14)/3 = 1
From the normal distribution table, the corresponding probability value is 0.84
P(11 ≤ x ≤ 17) = 0.84 - 0.16 = 0.68
% = 0.68 × 100 = 68%
3) P(x > 14) = 1 - P(x ≤ 14)
For x = 14,
z = (14 - 14)/3 = 0
From the normal distribution table, the corresponding probability value is 0.5
P(x > 14) = 1 - 0.5 = 0.5
% = 0.5 × 100 = 50%
4) P(5 ≤ x ≤ 17)
For x = 5,
z = (5 - 14)/3 = - 3
From the normal distribution table, the corresponding probability value is 0.00135
For x = 17,
z = (17 - 14)/3 = 1
From the normal distribution table, the corresponding probability value is 0.84
P(5 ≤ x ≤ 17) = 0.84 - 0.00135 = 0.839
% = 0.839 × 100 = 83.9%
