Question

Fifteen items or less: The number of customers in line at a supermarket express checkout counter is a random variable with the following probability distribution. 1 0.15 2 0.30 3 0.20 4 0.10 5 0.05 P(x) 0.20 Send data to Excel Part 1 of 7 (a) Find P(5). P(5) = 0 Part 2 of 7 (b) Find P(No less than 4). P(No less than 4) = Part 3 of 7 (c) Find the probability that no one is in line. The probability that no one is in line is

Answer 1

a)P(5 )=0.05

b)

P(no less than 4) =0.1+0.05 =0.15

c)

P(0) =0.2

d)

P(X>=3) =0.2+0.1+0.05 =0.35

e)

x	f(x)	xP(x)	x2P(x)
0	0.2000	0.0000	0.0000
1	0.1500	0.1500	0.1500
2	0.3000	0.6000	1.2000
3	0.2000	0.6000	1.8000
4	0.1000	0.4000	1.6000
5	0.0500	0.2500	1.2500
	total	2.0000	6.0000
	E(x) =μ=	ΣxP(x) =	2.0000
	E(x2) =	Σx2P(x) =	6.0000
	Var(x)=σ2 =	E(x2)-(E(x))2=	2.0000
	std deviation=	σ= √σ2 =	1.4142

μ=2

6)

σ=1.414

7)

P(takes more than 6 minutes) =P(at least 3 in line) =0.35