Assignment X4, Question X4.6

Hello one question here.

The solution uses 'z bar' which approximates z(1) and z(2). Why is this so? m is less than 20 here and is not large enough to use this approximation.

 

You're absolutely right in theory, but in practice (in the exam) this does tend to be ignored. Basically, best plan is to use the approximate formula but say in your answer (briefly!) that the validity of the test is questionable because the number of ages is less than 20.

 

Thank you

Thank you for taking time to reply my question