Question

j.d power and associates says the 60 % of car buyers now use the internet for research and price comparison.

a) find the probability that in a sample of 5 car buyers, all 5 will use the internet. ( I got 795.8????)

b) find the probability that in a sample of 5 car buyers, at least 2 will use the internet.

c) find the probability that in a sample of 5 cars buyers, more than 1 will use the internet

d) find the mean and standard deviation
( I got mean of 3??? and standard deviation of 2.24????)

Answer 1

Answer:

p = 0.6 and q = 0.4

a.

P(all 5 will use the internet) = (5 C 5) * (0.6)^5 * (0.6)^0 = 0.6^5 =  0.07776

b.

P(at least 2 will use the internet) = 1 - P(none will use) - P(one will use)

= 1 - (5 C 0) * (0.6)^0 * (0.4)^5 - (5 C 1) * (0.6)^1 * (0.4)^4

=1 - 0.01024 - 0.0768

= 0.9129

c.

P(More than one will use )

=P(X=2) + P(x=3) + P(x=4) + P(x=5)

= P(At least two)

=0.9129

d.

mean = n * p = 5 * 0.6 = 3

sd = sqrt(n *p*q) = sqrt(5 * 0.6 * 0.4) = 1.095