The probability of between 4 and 8 participating in a fight is: 84%
How to find the probability from z-score?
The formula for z-score here is:
z = (x' - μ)/σ
where:
x' is sample mean
μ is population mean
σ is standard deviation
We are given:
x₁ = 4
x₂ = 8
μ = 5
σ = 1
Thus:
z₁ = (4 - 5)/1
z₁ = -1
Similarly:
z₂ = (8 - 5)/1
z₂ = 3
Using probability from z-score formula gives us:
p-value = 0.84 = 84%