The employees of a firm that manufactures insulation are being tested for indications of asbestos in their lungs. The firm is requested to send three employees who have positive indications of asbestos to a medical center for further testing. If 30% of the employees have positive indications of asbestos in their lungs, find the probability that eleven employees must be tested in order to find three positives. (Round your answer to three decimal places.)

0.070

Step-by-step explanation:

Y = number on trial

Y has a negative binomial distribution

r = 3

P = 30% = 0.3 probability of positive indication.

P(Y = 11) probability of 11 employees that must be tested to get 3 positives

Y-1Cr-1*p^r*q^(y-r)

Y-1 = 11-1 = 10

r-1 = 3 -1 = 2

10C2 x 0.3³x0.7⁸

45x0.027x0.05764801

= 0.070

This is the probability that 11 employees must be tested to get 3 positives.

all three statements are true

step-by-step explanation:

a shipping fee of 5% is charged online with every item purchased online

first let's just take each option and calculate them based on this, to see if the answers matched

keith buys a 40 dollar book

40 x 0.05 = 2

therefore there will be a two dollar fee on keith's book

40 + 2 =42

the first statement is true

a chair costs $80

80 x 0.05 = 4

80 + 4 = 84

the second statement is true

george buys a 20 dollar calculator

20 x 0.05 = 1

20 + 1 = 21

the third statements are true

all three statements are true