A fair coin is flipped 60 times, what is the percent chance of flipping heads 25 or fewer times?
would you solve it this way?
binomal
B-(60,0.5)
P(X< or = 25)
so it's 60Cr * 0.5^(r) * 0.5^(60-r)
where r=0,1,2,3,4,5,......23,24,25
then that times 100 to get %.
=12.25%
That's ok!
It's a shortcut taken by comparing the Binomial distribution with the Normal distribution.
The calculation can then be done more quickly (especially when we'd have to sum a substantial number of terms of the Binomial expansion).
However, you'd need to have covered the Normal distribution for this.