Answer:
Step-by-step explanation:
To solve for this we would be using z score formula
z = (x - μ) / σ
x = raw score
μ = mean
σ = Standard deviation
We are told in the question to find the fraction of numbers between 80 and 120
let x1 = 80 and x2= 120 with the mean μ = 100 and standard deviation σ = 5.
z1 = (x1 - μ) / σ = (80-100) / 5 = -20/5 = -4
z2 = (x2 - μ) / σ = (120 - 100) / 5 = 20/5 = = 4
From tables, P(z <= -4) = 0.00003
P(z <= 4) = 0.99997
Then, the probability would give us, P(-4 ≤ z ≤ 4) = 0.99997 - 0.99997 =
