The score that cutt off the middle 50 percent of all scores is 43.2
Explanations:For a normal distribution, the normal value is the mean
It divides the curve in 50%-50%
Mean score, μ = 43.2
Standard Deviation, σ = 8.6
P(X≤a)=0.5
Use Z =(X-μ)/δ ~N(0;1)
b =(a-μ)/σ
P(Z≤b)=0.5
The value is b=0 (the mean for Z)
a=(b*σ)+μ
a=(0*8.6)+43.2
a=43.2
Therefore, the score that cutt off the middle 50 percent of all scores is 43.2
