Table 2.

Questions posed to a group of 122 undergraduate medical students to guess which well–known celebrity is older than the other*

Pair 1: Justin Bieber vs Miley Cyrus (19 vs 20)

Pair 2: George Clooney vs Brad Pitt (52 vs 49)

Pair 3: Madonna vs Susan Boyle (55 vs 52)

Pair 4: Beyonce vs Shakira (32 vs 36)

Pair 5: Dustin Hoffman vs Robert de Niro (76 vs 70)

Pair 6: Katy Perry vs Rihanna (28 vs 25)

Pair 7: Mick Jagger vs Paul McCartney (70 vs 71)

Pair 8: Lewis Hamilton vs Tiger Woods (28 vs 37)

Pair 9: Angela Merkel vs J. K. Rowling (59 vs 48)

Pair 10: Tony Blair vs George W. Bush (60 vs 67)

Pair 11: David Cameron vs Barack Obama (47 vs 52)

Pair 12: Ashton Kutcher vs Ben Affleck (35 vs 41)

Pair 13: Tom Cruise vs Nicole Kidman (51 vs 46)

Pair 14: Paris Hilton vs Jennifer Anniston (32 vs 44)

Pair 15: Jennifer Lopez vs Britney Spears (44 vs 31)

Pair 16: Eminem vs Jay–Z (40 vs 43)

Pair 17: Kim Kardashian vs Adele (33 vs 25)

Pair 18: Roger Federer vs Andy Murray (32 vs 26)

Pair 19: David Beckham vs Prince Harry (38 vs 29)

Pair 20: Elvis Presley vs Michael Jackson (42 vs 50)

*Correct answers (expressed in years of their age at the time of this exercise) are shown in brackets. The indicated age of individuals is relevant to October 17, 2013. For the last pair, the age at the time of death was being compared. The question was posed as: “Would you say that celebrity X is older than celebrity Y?” and possible answers were “Yes”, “No”, “Not sure” or “Blank” (see details in the text).