How do you do VCAA 2010 Exam 1 Core Q3?

[Comatose]

title says it all. question 3 of core exam 1 2010.

[jasoN-]

We know the median is 180 from the boxplot and since the distribution looks approx symmetric, we can equate mean ~180
From there, we know that 1 standard deviation away from the mean accounts for ~68% of values
Looking back at the histogram, add up columns to the left and right of the mean (1 by 1) until u get approx 68%
By using a ruler (hells yea) u get values 21%, 16%, 13.5%, 14.5% (ROUGHLY) which adds up to a total of 64.5% which is close enough to 68%
therefore 68% is covered by 2 bars to the left of the mean, 2 bars to the right of the mean
S.D = 180-178 = 2ºC (or 182-180)

This was just how I did it, can't really think of a more systematic approach to it

[Comatose]

thank you very much. that made things perfectly clear