Independent solution

How to solve this Exponential Distribution question

Setup

Setup

Write the median-to-mean relation for each of the three distribution families.

mexp=(ln2)μm_{\mathrm{exp}}=(\ln 2)\mu
mnormal=μm_{\mathrm{normal}}=\mu
muniform=a+b2=μm_{\mathrm{uniform}}=\frac{a+b}{2}=\mu

Model

Model

Each median is a fixed multiple of its distribution's mean.

m=cμ,c{ln2,1}m=c\mu,\qquad c\in\{\ln2,1\}

Compute

Compute

Replace the mean by twice its former value in the common relation.

mnew=c(2μ)=2(cμ)=2moldm_{\mathrm{new}}=c(2\mu)=2(c\mu)=2m_{\mathrm{old}}

Answer

Answer

The doubling property holds for the exponential, normal, and continuous uniform distributions.

all three(A)\boxed{\text{all three}\quad\text{(A)}}