If np 5 and nq5 estimate Pmore than 6 with n12 and p07 by us

If np >5 and nq>5, estimate P(more than 6) with n=12 and p=0.7 by using the normal distribution ; if np<5 or nq<5, then state the normal approximation is not suitable.

a) p(more than 6)= ___

b) the normal distribution cannot be used

Solution

As np = 12*0.7 = 8.4 and nq = 12(1-0.7) = 3.6 (which is < 5), normal approimation cannot be used as nq<5.

As one of the conditions of [np > 5] and [nq > 5] is violated,

Answer: b. the normal distribution cannot be used