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

Answer:

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

Step-by-step 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:

$P(x = 7) = _{10}C_7 0.15^{10-7}\times 0.85^7\\P(x = 7) = _{10}C_3 0.15^{3}\times 0.85^7\\P(x = 7) = 10\times 9 \times 8 \times 0.15^{3}\times0.85^7\\P(x = 7) = 720 \times .0034 \times0.32\\P(x = 7) = 0.78$

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