probability that a given driver is using a seatbelt

[nyesha]

In the United states, what is the probability that a driver is using a seatbelt?

 Driver using Seat Belt?
+----------+-----+-----+
| region   | yes |  no |
+----------+-----+-----+
| nothwest | 148 |  52 |
| midwest  | 162 |  54 |
| south    | 296 |  74 |
| west     | 252 |  48 |
+----------+-----+-----+
| total    | 858 | 228 |
+----------+-----+-----+

I added the totals together: 858 + 228 = 1086. Then I divided each "yes" amount by the 1086. I totaled that and got 0.77.

Then I added the "yes" and "no" amounts together, divided these amounts by the 1086, and then added to get 0.98.

Am I on the right track or way off?

 

[stapel]

The question asks for "the" probability. Why would two probabilities be the answer?

What is the total population in question? What portion of that population answered "yes"?

Eliz.