Intelligence is best defined as the ability to learn from experience, solve problems, and use knowledge to adapt to new situations.
a cluster of related items.
a general ability that underlies all mental abilities.
whatever intelligence tests measure.

Dr. williams conducted a survey in the mall, measuring the shopping habits of people ages 15, 25, 35, 45, and 55, with 10 people in each group. which of the following best describes her study? an experiment a cross-sectional study a case study a longitudinal study a double-blind study