A nutritionist has designed an intervention to motivate parents of preschool children to provide more fruits and vegetables to their children. To study the effectiveness of this intervention, the
nutritionist will conduct an experiment in which half of the selected study participants will receive
the intervention and the others will not. Study subjects will be recruited from families with children
who receive medical care for their children through the university health center. The nutritionist will
compare the amount of fruit consumed per day by the children in families who received the
intervention and by those who did not. Which of the following is true?