The Anonymous Widower

My Mother And Her Brother Shared a Birthday

My mother was born on the 22nd December 1911 and her eldest brother; Leslie had been born on the same day about eight years earlier.

These two pictures were drawn by Leslie of my mother as a child and his wife Gladys in later life.

Cousins Reunited

Gladys was a first cousin to my mother and her brother.

My mother and her brother were close and always phoned each other on their birthday and had a long chat.

Last Sunday, which would have been their birthday., I was thinking about my mother and her brother  and wondered, if any other siblings shared a birthday. Other than twins of course.

It’s explained in the Wikipedia entry for the Birthday Problem, where this is the first paragraph.

In probability theory, the birthday problem asks for the probability that, in a set of n randomly chosen people, at least two will share the same birthday. The birthday paradox refers to the counterintuitive fact that only 23 people are needed for that probability to exceed 50%.

It would appear that to be certain in siblings to have a fifty percent chance of having two birthdays the same, you would need twenty-three siblings. My mother and her bother were only one of nine, so they got good odds.

December 27, 2024 - Posted by AnonW | World | My Family, My Mother, Siblings, Statistics