Question

In a national survey college students were​ asked, "How often do you wear a seat belt when riding in a car driven by someone​ else?" The response frequencies appear in the table to the right.​ (a) Construct a probability model for​ seat-belt use by a passenger.​ (b) Would you consider it unusual to find a college student who never wears a seat belt when riding in a car driven by someone​ else?

Response	Frequency
Never	131
Rarely	331
Sometimes	524
Most of the time	1169
Always	2495

(Round to the nearest thousandth as needed)

Answer 1

(a) Construct a probability model for​ seat-belt use by a passenger.​

From given frequency distribution, the required probability model is given as below:

Response	Frequency	Probability
Never	131	131/4650 = 0.028
Rarely	331	331/4650 = 0.071
Sometimes	524	524/4650 = 0.113
Most of the time	1169	1169/4650 = 0.251
Always	2495	2495/4650 = 0.537
Total	4650	1.000

(b) Would you consider it unusual to find a college student who never wears a seat belt when riding in a car driven by someone ​else?

The probability that a college student who never wears a seat belt when riding in a car driven by someone ​else is given as 131/4650 = 0.028.

This probability is less than 0.05.

We consider the probability as unusual when it is less than 0.05.

So, we would consider it unusual to find a college student who never wears a seat belt when riding in a car driven by someone ​else.