Of the following, which one is an observational study?
a. asking people for their opinion on the taste of a new cereal
b. checking the effectiveness of a new headache medicine by giving one group the new medicine and one group acetaminophen
c. tracking the temperature in a city over a five year period measuring the average d. strength of a batch of metal by stressing some sample pieces until they deform

hello from mrbilldoesmath!

answer:

the domain is the set { -2, 0, 2, 3}

discussion:

the domain is the set of x values in the ordered pairs (x,y). taking the x, or first component, of each ordered pair gives   -2, 0, 2, 3.

you,

mrb

if you need , reply with more info. u.

irrational, then, just means all the numbers that aren't rational. every integer is a rational number, since each integer n can be written in the form n/1. however, numbers like 1/2, 45454737/2424242, and -3/7 are also rational, since they are fractions whose numerator and denominator are integers.

step-by-step explanation: