Does it want it in standard form e.ge 0.00002 = 2 x 10(to the power of) -5, or is that in m and it wants you to convert it to micrometres?
#1,4 are biased because the number range is too wide. (include #2 if the question allows)
#1: 31-20 = 11
#2: 29-21 = 8
#3: 30-23 = 7
#4: 50-15 = 35 (OMG that's so biased!)
so if the three surveys are eliminated, then the answer to the second question is 23%.
Hope that helps :)
10 and -4 can add up to give 6 and multiply to give -40
M=-4
The number with x is always going to be the slope
Y-intecept=9