Determine whether the samples are independent or dependent. the effectiveness of a new headache medicine is tested by measuring the amount of time before the headache is cured for patients who use the medicine and another group of patients who use a placebo drug. explain your decision.

An independent variable is one which can be changed or manipulated in an experiment. The effect of the independent variable is observed on the dependent variable. The dependent variable is the one which does not change or manipulated in an experiment by the investigator. The changes that occur in the dependent variable with respect to the independent variable is the outcome of the experimentation process.

In the given situation, the medicine and the placebo drug are the independent samples whereas the effect of the medicine and placebo drug can be observed on the time they require to cure the headache is the dependent variable.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .