What is the first quartile (q1) of the data set? 51, 42, 46, 53, 66, 70, 90, 70
80
59.5
61
48.5

Values in increasing order 
42 
46 
51 
53 
66 
70 
70 
90 

Lower quartile : There are 8 observations 
If there are in observations, compute the lower quartile as follows: 
if n/4 is an integer, compute the lower quartile as 
(x[n/4]+x[n/4+1])/2 :: (x[8/ 4]+x[8 /4 +1])/2 
if n/4 is not an integer, compute the lower quartile as 
x[k], where k is the smallest integer exceeding n/4:: 2 = 2 
Lower Quartile : Average of observations 2 and 3 is -- 
= (46+51)/2 = 48

Ifound this on google “that means that the graph of a function with direct variation has these features: it is a straight line: because the slope is the ratio y/x = k. it passes through the origin (0,0): because y = kx = k (0) = 0.” i hope this you for what your looking for