Barbara is converting 78°F to degrees Celsius. First, she subtracts 32 from 78. What is the next step? multiply 46 by 5/9
multiply 46 by 9/5
add 273 to 46
subtract 273 from 46

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .