A florist wants to determine if a new additive helps extend the life of cut flowers longer than the original
additive does. The florist selects 20 flowers of different
types and puts each flower in its own vase with the
same amount of water. She positions the vases so they
also receive the same exposure to light. She numbers
the flowers 1-20, and places these numbers on equal-
sized slips of paper. The slips are placed in a hat and
mixed thoroughly. A slip is chosen and the
corresponding flower receives the new additive. After
the hat is shaken, another slip is chosen and the
corresponding flower also receives the new additive.
This procedure continues until 10 flowers have been
assigned to receive the new additive. The remaining 10
flowers receive the original additive.