# two population proportions

#### osamastat

##### Member
Self–reported injuries among left and right- handed people were studied in a survey of 1896 college students in Benghazi University. Of the 180 left-handed students, 93 reported at least one injury, and 619 of the 1716 right–handed students reported at least on injury in the same period.
Do these data gave a strong evidence to say that the proportion of the right-handed students is less than the proportion of the left- handed students by 10%

I assumed the right handed students to be secomd population and the left handed people the first population
the form of the null and alternative hypothesis is :
Ho : P2 - P1 >= 10%
H1 : P2 - P1 < 10%
is my solution correct?

are they ok?

#### katxt

##### Well-Known Member
I assumed the right handed students to be secomd population and the left handed people the first population
the form of the null and alternative hypothesis is :
Ho : P2 - P1 >= 10%
H1 : P2 - P1 < 10%
is my solution correct?
Sample P2 is about 35% and P1 is about 50%, so no way is P2 - P1 >= 10% a suitable Ho.
Do you have to do a hypothesis test? They can be very confusing. Most people would just find a suitable confidence interval for the difference and see if 10% lies in it or not.