V
verma.kunal13
Member
In this question, why do we integrate from 0 to y/2 and why not -infinity to y/2. Normal distribution ranges from -infinity to infinity. What wrong am I thinking? Help. Thanks.
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Hemant Rupani
Senior Member
I think its an erratum, lower value should be \( -\infty \)
Hemant Rupani
Senior Member
Ohhhh! Value from \( -\infty \) to 0 is constant(0.5) so derivative must be zero.
That gives valuation before derivative is \( -\infty \) to y/2 and after derivative is from 0 to y/2.
That gives valuation before derivative is \( -\infty \) to y/2 and after derivative is from 0 to y/2.
M
Margaret Wood
Member
Sorry to cause confusion. We should integrate from minus infinity to y/2. We'll put a note in the corrections document on the website. (Note that this question is Q1.23 in the 2015 CMP.)
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J
Jammy
Member
Hi, could someone break down the use of Leibnitz's formula here for differentiating the integrating (pg3 Tables)
b(y) = 1/2y
So b'(y) = 1/2
a(y) = -infinity
So a'(y) = 0
then we just need f[b(y),y)which is we take f(x,y) and replace x with 1/2y
J
Jammy
Member
The part I couldn't figure was the 3rd term in the formula.
How is it 0? How do differentiate that exponential term?
How is it 0? How do differentiate that exponential term?