dse 2011

[seema]

A doctor testing a diagnostic tool for a rare disease wants to minimize the chance that the test will find a patient to be healthy when she is in fact sick (the null hypothesis being that the patient is healthy). The doctor should minimize the probability of;
1) Type I error which would denote a false positive
2) Type II error which would denote a false positive
3) Type I error which would denote a false negative
4) Type II error which would denote a false negative

[Ram]

I guess the answer for this will be option 4. because he wants minimize the chance that the test will find a patient to be healthy when she is in fact sick if he wants to minimize the chance that the patient to be sick when she is in fact healthy then it is option 1. I am not exactly sure about this because am new to economics field ( am from so called engineering background :P..) let's see what senior members will reply..

[ritu]

see it has to be a minimisation of type 2 error but i dont kno abt this false positive nd negative!!!!!

[Ram]

Hi ritu,

   You can check this to get an idea about false positive and negatives
   http://en.wikipedia.org/wiki/Type_I_and_type_II_errors

[ritu]

then d is the correct option...:)

[Erika]

this is based on hypothesis testing.

Type I error is : REJECTING a TRUE hypothesis.
Type II error is : ACCEPTING a FLASE hypothesis.
As you can tell, both are ERRORS, we simply need to find out which one.

1. our null hypothesis/true hypothesis is H0=Patient is healthy and is found healthy
2. alternate hypothesis/false hypothesis is H1=Patient is sick and is found healthy.

clearly, he should minimise 2.

thus, type 2 error should be minimised, ie the error of accepting a false. (d)

[Sinistral]

but key says option (b).
which one is the right answer?