Question

which of the following events are disjoint?

choose a student at random from a statistics class. event a is that the student is a psychology major. event b is that the student is a statistics major.

choose a student at random from a statistics class. event a is that the student is at least 58\ tall. event b is that the student weighs at least 160 pounds.

choose a student at random from a statistics class. event a is that the student plans on attending a party on saturday. event b is that the student plans on studying all day sunday.

choose a student at random from a statistics class. event a is that the student is a junior. event b is that the student is a senior.

Explanation:

Disjoint events are those that cannot occur at the same time (i.e., their intersection is empty).

• For the first option: A student could be both a psychology and statistics major (e.g., double major), so not disjoint.
• Second option: A student can be at least 5'8" tall and weigh at least 160 pounds simultaneously, so not disjoint.
• Third option: A student can plan to attend a party on Saturday and study all day Sunday, so not disjoint.
• Fourth option: A student cannot be both a junior and a senior at the same time, so these events are disjoint.

Answer:

Choose a student at random from a statistics class. Event A is that the student is a junior. Event B is that the student is a senior.