7. On a group trip to a certain city, 20 people who were 25 years old, 20 people who were 30 years
old, and 20 people who were 35 years old
purchased tickets for a bus tour of the city. No
one else purchased tickets for the bus tour. A
30-year old who had purchased a ticket became
ill and did not go on the bus tour, and everyone
else who purchased a ticket went on the bus tour.
Which of the following statements is true?
(A) The standard deviation of the ages of the
people who went on the bus tour is greater
than the standard deviation of the ages of
the people who purchased tickets.
(B) The standard deviation of the ages of the
people who went on the bus tour is less than
the standard deviation of the ages of the
people who purchased tickets.
(C) The standard deviation of the ages of the
people who went on the bus tour is equal to
the standard deviation of the ages of the
people who purchased tickets.
(D) There is not enough information to
determine which standard deviation is
greater.