X= a telesales representative making a sale on a customer call
(a) X∼Bin(10,0.15)
P(X=0)=(010)(0.15)0(1−0.15)10=0.1969
The probability that No sales are made in 10 calls 0.1969
(b) X∼Bin(20,0.15)
P(X>1)=1−P(X=0)−P(X=1)==1−(020)(0.15)0(1−0.15)20−−(120)(0.15)1(1−0.15)19=
=1−0.03875953108−0.136798345=
=0.82444212391 The probability that more than 1 sales are made in 20 calls is 0.8244.
(c) μ=np≥5
0.15n≥5=>n≥34 The least number of calls each day is 34.
(d)
P(X≥1)=1−P(X=0)>0.95
1−(1−0.15)n>0.95
(0.85)n<0.05
n≥19 The least number of calls is 19.
Comments
Leave a comment