I want to ckeck if I am correct in how to calculate quartiles (Q1, Q2, Q3) in a pdf graph function and ask one question. I am working on a function $(3/16)*(x+2)^2$ on $ [-4,0]$
I know that the second quartile is the Median and the correct integral has form $$\int_{-4}^{M} \frac3{16}(x+2)^2dx =\frac 12$$ And from that M is calculated. However, what would be the values of the integral be for Q1 and Q3 and why?
Thank you