Which two ratios form a proportion? a) 3 : 4 and 6 : 12 b) 3 : 4 and 9 : 15 c) 3 : 4 and 12 : 18 d) 3 : 4 and 15 : 20

The brain volumes (cm cubed) of 50 brains vary from a low of 904 cm cubed to a high of 1488 cm cubed. use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 175.5 cm cubed, assuming the estimate is accurate if it is within 15 cm cubed

With finding limits of multi variable !

The weight v of an object on venus varies directly with its weight e on earth. a person weighing 120 lb on earth would weigh 106 lb on venus. how much would a person weighing 150 lb on earth weigh on venus?