Please Help!! A study determined that 15% of a population use a certain brand of laundry detergent. What is the probability that more than 2 shoppers selected at random from 12 shoppers use that brand of detergent?

Question

Please Help!! A study determined that 15% of a population use a certain brand of laundry detergent.  What is the probability that more than 2 shoppers selected at random from 12 shoppers use that brand of detergent?

anonymous · Answer

@kropot72

kropot72 · Answer

You can use the binomial distribution to solve this.

anonymous · Answer

i tried and i get it wrong everytime

kropot72 · Answer

Can you post some of your attempt?

anonymous · Answer

i used my calculator for it binompdf(12,.15,2)

anonymous · Answer

i got .2923

kropot72 · Answer

You need to find the probabilities that 0, 1 and 2 people use the brand. Then add these three values. Then subtract that sum from 1.000 to find the required probability.

anonymous · Answer

how? Im really not good at probabilities @kropot72

anonymous · Answer

@ganeshie8

anonymous · Answer

12C2

anonymous · Answer

it should be a decimal i got 66

anonymous · Answer

resourcesdev.ck12.org/2017ffeb6a6069d5291bbfccb7c41f2b.pdf

anonymous · Answer

i think @kropot72  will be correct.he knows very well

anonymous · Answer

im just not sure on how to find those probabilities @kropot72 if you show me i will still do all the work so i learn

anonymous · Answer

0.225 is the answer?

anonymous · Answer

howd you figure that?

anonymous · Answer

15/100*15/100/12C2 ..idk the method simply trying

kropot72 · Answer

$$\large P(0)=0.85^{12}$$
$$\large P(1)=12\times0.15\times0.85^{11}$$
$$\large P(2)=66\times0.15^{2}\times0.85^{10}$$
The required probability is:
1.0000 - {P(0) + P(1) + P(2)} = you can calculate

anonymous · Answer

.2642? @kropot72

anonymous · Answer

10000-0.7357=

kropot72 · Answer

Yes, you are correct!