I am stuck with question number four in the pictures attached. The sheet gives information on which graphs can be used to find which information. How do I find variation in the weather patterns by using the dot plot and the bar graph?
link to graphs: http://media.apexlearning.com/One-Off/200901/06/fb431897-4348-4425-8343-ce0852614a82.pdf
link to assignment questions: http://media.apexlearning.com/One-Off/201210/30/52e070d0-83a0-4fac-bcee-6c77f9967d47.pdf
At first, consider line graph. It gives the same information as the bar graph, but line graph combines data from both cities which makes comparing easier.
From the line graph we see those differences:
1) while Portland's graph has one minimum (near July) and one maximum (near December) and is monotone between them, the Tampa's graph has more oscillations (the additional one is at March-April).
2) one graph has maximum near the minimum of the second graph, and vice versa. In another words, when rainfall is maximum at one city, it is minimum at the other.
3) in general, Tampa's changes during one month are more rapid than Portland's (and this is better seen at the line graph because it has lines between points).
4) Tampa has greater minimum and maximum (almost 2 and 8) than Portland (less than 1 and 6).
Actually, we can observe this from bar graphs (as you suggest) also but with less ease.
Now go to the dot plots. They group data by value, not by argument (independent variable), as all other graphs and charts do here.
1) dot graphs also show us the difference between minimums and maximums. Portland's minimum is 1 against Tampa's 2, and maximums are 8 and 6.
2) Tampa's graph has a "hole" at 5, i.e. no month when rainfall is 5 inches.
3) the most frequent value is 2 for both cities, but Tampa reaches it 5 times, not 4 as Portland.
4) (not differences but similarities): all other values except the most frequent are reached 1 or 2 times in both cities, the number of different values is 6 for both and most dots are located toward the minimum end.
Hope this helps.