Reisdual Plot help? + help with 2012 exam

[shinymeowstic]

Hello, I'm wondering if you need to use the calculator, and put ALL the values into it, to get the residual plot (taking more time), or can you tell just by looking? For example, a question gives you the scatter plot with the regression line, and then gives you 5 residual plots to see from, and pick which one is the correct one, will I need to use up extra time to figure this question out, or is there a faster way?

Also, I do not understand the 1st question in the 2012 exam 1. Adding south and south east together makes 36%, not 16%! Have I misread the question or is there something else to it? (the question is here, on page 4 > http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2012/2012furmath1-w.pdf )

thank you!

[LiquidPaperz]

q1 asks what is the most frequent wind direction, adding south and south east means your adding how frequent the wind goes south and also how frequent it goes in the south east direction - both two separate directions just like 180 degrees and 140 degrees if you do geo + trig. the question asks what was the most frequent wind direction, not wind directions hence E would be correct answer.

[tan(k)]

I think you mean the second question...

At the top of the graph at the beginning of the question it says n=214. This means that the total number of wind directions recorded was 214. To find the percentage of days where the wind direction was east or south-east you have to find the total frequency (which you find by adding the two columns) then find as a percentage of 214.

=35/214 * 100
=16%

[shinymeowstic]

ah I see now, thank you!