The Math/stats thread

[MTLskyline]

I had a midterm examination in my stats/probability class yesterday (yes on a Sunday....). I'm trying to figure out if I got the right answer or not on one of the questions.

 

Everyone had problems with this question it seemed. Yet the question seems pretty simple on the surface!

 

The question was about the number of coffee refills ordered at a truck stop.

 

# of refills | Probability

0 | 0.3

1 | 0.4

2 | 0.2

3 | 0.1

 

a) What is the probability of two randomly selected truckers will each order the same number of refills?

 

I put:

(0.3) (0.3) + (0.4)(0.4) +(0.2)(0.2) + (0.1)(0.1)

= 0.09 + 0.16 + 0.04 + 0.01

= 0.3

 

Is that correct?

 

Thanks!

[jesseps]

It seems correct from Wolfram Alpha perspective

 

Answer

[Malek]

This seems correct.