About whose death did Dorothy Parker state, "How can they tell?"

Calvin Coolidge was the 30th President of the United States, and his highly reserved character in social settings led to the nickname “Silent Cal”. A few years after his death in 1933 two similar anecdotes began to circulate about the spoken reaction to the news of Coolidge’s demise. Reportedly, when the wit Dorothy Parker was notified she said:
"How can they tell?"
Also, when the raconteur Wilson Mizner was told he said:
"How do they know?"

In conclusion, based on current evidence the acerbic remark in the 1936 citation should be credited to Dorothy Parker. There is some evidence that Wilson Mizner employed the same jape, and he may have constructed it independently.