# Probability

In large lot of electric light bulbs 5% of the bulbs are defective.calculate the probability that a random sample of 20 will contain at most 2 detective bulbs

1. 👍 0
2. 👎 0
3. 👁 203
1. The outcome consists of individual answers of true/false, probability remains constant throughout, use Binomial probability.

P(n,r,p)=nCr*p^r(1-p)^(n-r)
n=size of sample
r=(exact)number of outcomes each with probability of p

At most 2 means 0,1 or 2.

For example,
P(20,2,0.05)=20C2*0.05^2*0.95^18
=(20*19/(1*2))*0.05^2*0.95^18
=0.1887

Complete the solution by adding the two other terms.

1. 👍 0
2. 👎 0
posted by MathMate

## Similar Questions

1. ### Maths

In a large lot of electric light bulbs,5% of the bulbs are defective.calculate the probability that a random sample of 20 will contain at most 2 defective bulbs? Try ;->Pr=nCx p^xq^n-x .pr(2D)=20C2(0.05)^2(0.95)^18;->=2.2/ANS

asked by Destiny on June 5, 2014
2. ### Probability

A company produces light bulbs, and finds that approximately 2% of the light bulbs they produce are defective. The company wants to make a money-back guarantee that in every box of 10 light bulbs, no more than 1 will be defective.

asked by Peanut on April 28, 2015
3. ### math

A manufacturer of light bulbs knows that 3% of the production of their 60W bulbs will be defective. What is the probability that exactly 5 bulbs in a carton of 144 will ne defective? Did not understand the posted answer before,

asked by Jeff on January 26, 2011
4. ### math

A manufacturer of light bulbs knows that 3% of the production of their 60W bulbs will be defective. What is the probability that exactly 5 bulbs in a carton of 144 will ne defective?

asked by Jeff on January 26, 2011
5. ### Statistics

A box contains 12 lights bulbs, of which 4 are defective. All bulbs look alike and have equal chance of being chosen. 3 light bulbs are selected from the box to check the quality. a. List all the possible outcomes b. find the

asked by Yvonne on November 9, 2011
1. ### Statistics

If 5% of electric bulb manufactured by a company are defective find the probability that in a sample of 100 bulbs. (1)None if defective (2) 5 bulbs are defective e -5=0.007

asked by Lara on May 19, 2019
2. ### Math

A firm manufactures light bulbs and those that come out of the assembly line are either defective or good. Every five bulbs that come out, 1 is defective. If 3 bulbs are selected at random, what is the probability that: (i) All 3

asked by Maureen on May 6, 2013
3. ### finite math

a quality control engineer at a light bulb plant estimated that 1% of the bulbs it sells are defective. if you purcgase a package of 3 bulbs what is the probability that exactly one of them is defective?

asked by ophelia on March 24, 2011
4. ### Probabilities

Need some help please! A box contains four good light bulbs and three defective ones. Bulbs are selected one at a time (without replacement). Find the probability that the second defective bulb is found on the third selection.

asked by Bianca T on June 10, 2015
5. ### finite math

a quality control engineer at a light bulb plant estimated that 1% of the bulbs it sells are defective. if you purcgase a package of 3 bulbs what is the probability that exactly one of them is defective?

asked by ophelia on March 24, 2011

More Similar Questions