The ages of members of an online gaming group are normally distributed with a mean of 23 years and a standard deviation of 4 years. there are 300 members in the group. about how many members are expected to be between 15 years old and 31 years old? 204 264 270 285

To get the number of members between 15 years and 30 years we proceed as follows:
z=(x-μ)/σ
where:
mean,μ=23
standard deviation, σ=4 years
thus
P(15<x<31)
when x=15
P(x<15)
z=(15-23)/4
z=-2
thus
P(x<15)=P(z<-2)=0.0228

when x=31
z=(31-23)/4
z=2
thus
P(x<31)=P(z<2)=0.9772
Hence:
P(15<x<31)=0.9544
hence the number of members between that age was:
0.9544×300
=286.32 people
~285 People
285 people