Re: ISI Interview Question

Posted by Asd1995 on Jun 18, 2017; 5:31am
URL: http://discussion-forum.276.s1.nabble.com/ISI-Interview-Question-tp7605699p7605757.html

If you're preparing for ISI interview, they scrapped asking math questions last year.

ANnyway,

If a polynomial with real coefficients has 1 real root, then imaginary roots occur in conjugate pairs (a+bi,a-bi)

Since this has a degree of 2, it must have both roots real. Discriminant (b^2-4ac) >=0

so A^2-4>=0 or A belongs to the set of all real values except from -2 to 2.

So permitted values in our set are [2,5] so success= 0.6

Probability Mr. Y picks out something from [2,5]= F(5)-F(2) where F is cdf of the distribution.

First I believe we have to normalise the pdf here, so that INTERGRAL f for all values of a=1

so f(a)=2a/25

F(a)= a^/25

So success= 1-4/25=21/25