Personal statement to apply for graduate school with a change in major
People's interests change.  This doesn't require an explanation.  Here's an example:  I started college unsure whether to major in music or math.  I started out doing both.  It worked great the first semester.

Second semester: I got to my first day of Calculus II a few minutes late, and had to sit in the back.  It was a terrible room, long and narrow, and I felt disconnected from the teacher, and completely lost.  I was a pretty immature 17yo, and decided then and there to drop the class without giving it even a second chance.

Fast forward: I did the music degree, worked in an orchestra job for several years, paid off what I owed a relative for my cello, and went back to school for math and computer science.  I spent a year and a half taking math and CS courses, and got a programming job in my college's IT department.  I found out COBOL was boring, and applied to grad school.

In my personal statement I left out ALL of the above, and talked instead about my interest in combining math and computer science.

I didn't say, If I never play Ravel's Bolero again, it will be once too often.  I didn't say, As a COBOL programmer the closest I got to using my math was calculating GPAs.

Math is the language of science.  Statistics help us make sense of experimental results.  There's plenty of positives about statistics you can talk about in your personal statement.

There is no need to cover whatever meandering route got you to statistics.  All the committee will want to know is whether you are academically prepared for graduate study in statistics, and whether you have the imagination and commitment to do original research.