From Mike:

I heard this story from one of my math teachers in elementary school.

His mother had just purchased a house in Chesterfield, Indiana. Whenever she did house work, she always heard someone whistling a tune. At first, she thought it was her imagination. But every time she did any kind of house work, she heard this whistling.

She thought someone might be playing a prank on her but she could never find anyone around. Then she thought she might be going crazy. Finally, while talking to a neighbor one day, she told the neighbor about this.

The neighbor smiled and said, "Oh, that must be the old lady who used to live there. She was always doing some sort of house work that's how she died, you know. And she always whistled while she worked."