Statistics, Normal Distribution - IB Mathematics HL
Let the random variable F denote the family income, so that
the probability is
Using GDC Casio fx-9860G SD
MAIN MENU > STAT>DIST(F5)>NORM(F1)>Ncd>
Setting Lower: 15,000
We find that the probability is 0.2047
Therefore, 20.5% of the families will benefit from this new tax law.
Hope these help!!