1. anonymous

2. jtvatsim

The most important thing to know with box plots is where the "Quartiles" are and what the mean. Here's a diagram:|dw:1439235482846:dw|

3. jtvatsim

So, Q1 marks the spot where 25% of the data is to the left, the median marks the spot where 50% of the data is to the left, and Q3 marks the spot where 75% of the data is to the left. Let's identify Q1 and Q3 in your question first.

4. jtvatsim

So, it seems to me that Q1 = 1 year and Q3 = 6 years in your question. Do you agree with that?

5. anonymous

Yes i do

6. jtvatsim

Alright, perfect. So, now we need to figure out what the percentages translate to in our question.

7. jtvatsim

We have 40 schools. So some important percentages will be: 25% of 40 = 10 50% of 40 = 20 75% of 40 = 30

8. jtvatsim

Our job is to figure out how many schools are between Q1 and Q3 (that is the same as more than 1 and less than 6)

9. jtvatsim

|dw:1439235877341:dw|

10. jtvatsim

|dw:1439235933747:dw|

11. jtvatsim

I haven't fully explain the diagrams I just posted, but can you see the reasoning?

12. anonymous

Yes

13. jtvatsim

Perfect! Than you are done! P.S. In general 50% of the data is always between Q3 and Q1. So we could have solved this problem by just noticing that the question was asking for the data between Q3 and Q1, which would have just been 50% of 40 = 20.

14. anonymous

20 schools

15. jtvatsim

That is it!

16. anonymous

Thank you so much i appreciate it (:

17. jtvatsim

You're welcome! Good luck!