Question

Eighty-five percent of the people that use the Internet order something online. Find the probability that only 7 of 10 Internet users will order something online

Answer 1

the probability that 7 out 10 Internet users will order something online is 0.78 or 78%

Explanation:

Given that:

Internet users who order something online = 85%

To find:

Probability that 7 out of 10 Internet users will order something online ?

Solution:

This problem is of binomial distribution of probability.

where, p = 0.85

q = 1-p = 0.15

r = 7 and

n = 10

Formula is given as:

`P(x = r) = _nC_r q^(n-r)p^r`

Putting all the values:

`P(x = 7) = _(10)C_7 0.15^(10-7)* 0.85^7\\P(x = 7) = _(10)C_3 0.15^(3)* 0.85^7\\P(x = 7) = 10* 9 * 8 * 0.15^(3)*0.85^7\\P(x = 7) = 720 * .0034 *0.32\\P(x = 7) = 0.78`

So, the probability that 7 out 10 Internet users will order something online is 0.78 or 78%.