Question

Talia tossed a penny many times. She got 20 heads and 55 tails. She said the experimental probability of getting heads was

20
55
. Explain and correct her error by completing the sentence. Enter your answer as a simplified fraction.

Answer 1

For this case we know that in many times a penny shoes 20 head and 55 tails so then the total of trials are:

`n = 20 +55=75`

Then we are interested in the probability of getting heads and if we use the Laplace formula we have:

`p =(Possible)/(total)`

And the correct way would be:

`p =(20)/(20+55)=(20)/(75)`

If we simplify we got:

`p =(4)/(15)`

And the error was because she use 55 as the total number of trials and that's not the size of the sample space and for this reason she got
`(20)/(55)`

Explanation:

For this case we know that in many times a penny shoes 20 head and 55 tails so then the total of trials are:

`n = 20 +55=75`

Then we are interested in the probability of getting heads and if we use the Laplace formula we have:

`p =(Possible)/(total)`

And the correct way would be:

`p =(20)/(20+55)=(20)/(75)`

If we simplify we got:

`p =(4)/(15)`

And the error was because she use 55 as the total number of trials and that's not the size of the sample space and for this reason she got
`(20)/(55)`