The Alvin Secretarial Service procures temporary office personnel for major corporations. They have found that 40% of their invoices are paid within ten working days. A random sample of 12 invoices is checked. What is the probability that exactly 10 of the invoices will be paid within ten working days?

Answer:

Given :

The probability of success, $p = 0.40$

The sample size, $n = 12$

Solution :

→ The probability that exactly 10 of the invoices will be paid within ten working days :

$P (x = 10) = (\binom{n}{x}) p^{x} (1 - p)^{n - x} |_{x = 10}$ $= (\binom{12}{10}) {0.4}^{10} (1 - 0.4)^{12 - 10}$ $= 0.002491$

adbhutah.com

Articles: 1285