Probability Questions Before College: Tablets & Taste Test

[B2k]

jus before i go back to college trying to get a bit of revision done..
however i seem to have a block on this probability question...

a company makes tablets.. 94% would pass a disintegration test.. an inspector selects 6 at random at least 4 would have to pass, what is the proability of passing this test..?

and.. a study is conducted with 8 people tasting two products.. one with an additive.. 6 people select as product one having the additive.. can people tell a difference? use probabilty to justify your answer.. just wondering how best to prove that statement?

 

[statdad]

What have you tried for each one?

 

[B2k]

well for the second part its obvious that people can tell a difference if 6 can identify it.. that's just a straightforward probability q that can be done with the formula p=a/s.. i can do the math for that.. just how to phrase it..

the first part, I am a bit stumped.. the answers i get seem far out.. I am not sure am i using the % part of it right..

 

[tiny-tim]

Welcome to PF!

Hi B2k! Welcome to PF!

the first part, I am a bit stumped.. the answers i get seem far out.. I am not sure am i using the % part of it right..

So show us what you've done …

 

[Ygggdrasil]

Here's how I would approach #2. Consider what happens if people CANNOT tell the difference between the two products and just choose randomly. What is the probability that 6/8 choose the correct product?

 

[statdad]

You replied

Here's how I would approach #2. Consider what happens if people CANNOT tell the difference between the two products and just choose randomly. What is the probability that 6/8 choose the correct product?

Almost. If they cannot tell the difference, and simply make selections at random, you want the probability that at least six of the eight choose this way?

What type of calculation do you need to do to find that probability?