99 is a pretty big number, we can use normal distribution. Average is 49.5, Standard-deviation is $\frac{\sqrt{99}}{2}=4.975$ ; Excel gives the result :
loi.normale(56; 49.5;4.975;True)=0.90
90% of scores are lower than 56.
99 is a pretty big number, we can use normal distribution. Average is 49.5, Standard-deviation is $\frac{\sqrt{99}}{2}=4.975$ ; Excel gives the result :
loi.normale(56; 49.5;4.975;True)=0.90
90% of scores are lower than 56.