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Identifying Independent and Dependent Variables

let's take a look at identifying

independent and dependent variables the

key with identifying independent and

dependent variables is to think simply

about this what is in control once we

determine what the variables are for a

given situation so what controls what

well let's take a look at this first one

and see if we can't figure this out

first of all we want to come up with

what exactly are the things that could

change in a situation so first one says

car insurance costs increase with

traffic violations and accidents well

what do we have for variables in other

words what things can change well we

have the car insurance costs those could

change in fact it says they increase

with traffic violations and accidents

well what's the other thing that we

would need to know we'd need to know how

many traffic violations and accidents

there were okay so what controls what

well do the number of traffic violations

and accidents control the cost or do the

cost control how many traffic violations

and accidents you've had well there

might be some slight control if your

costs are very high to not have traffic

violations or accidents but I think that

it's pretty clear that the number of

traffic violations and accidents would

control our car insurance costs so

that's in control so first thing I want

to say that brings that one up is or

that comes up with that one is don't

overthink it sometimes we can kind of

convince ourself of either way in some

of these situations but don't overthink

it think about what you would need to

know to determine the other one so again

independent number of violations in

accidents the dependent is the cost of

the insurance all right let's take a

look at this next one ice cream sales

increase as the temperature increases

okay so what do we have for variables

well we have ice cream sales and we have

the temperature all right so what

controls what what's in charge here well

let's see do the ice cream sales control

what the temperature is outside or does

the temperature outside control the ice

cream sales well seems to me that when

it's warmer and this is kind of what it

says when it's the sales increase when

it's warmer so being warmer this is

going to be in control and that is our

independent variable that means the

increase sales or the sales must be the

dependent variable okay now this next

one here we have it says will charge is

$25 per hour to fix your computer now

don't be thrown off by that $25 per hour

the key it to remember here when we're

identifying independent and dependent

variables is that we want variables we

want things that could possibly change

well does the $25 per hour change no

what could we figure out if we know that

he charges $25 per hour well we could

figure out how much he's going to charge

us okay well what do I need to know in

order to figure out how much he's gonna

charge us if I know he charges $25 per

hour well I need to know how many hours

he worked okay so what's in control are

the overall charges in control or are

the number of hours that he worked in

control well which would we need to

divide the other way we would need the

number of hours that he worked to

determine the total cost for fixing the

computer so the number of hours in this

case will be the independent variable

and the dependent variable is going to

be

what the charges are okay let's look at

this last one states with a larger

population have more seats in the House

of Representatives all right so what do

we have for variables well we've got

population and the seats in the House of

Representatives now we need to think

about what controls what so does the

population determine how many seats they

have or does the number of seats they

have in the government determine how

many people live in that state hmm well

I think it's pretty clear that the

population determines the number of

seats so the population will be our

independent variable and the number of

Representatives the number of seats

would be the dependent variable so

identifying independent dependent

variables my first tip again to you is

don't overthink it sometimes you can

convince yourself that it might be

something that it probably isn't

secondly make sure you're choosing a

variable okay 25 sometimes I see that

when there's a number I see students

want to pick that as the independent or

dependent variable the problem with that

is a number is not a variable

it doesn't change remember the the word

variable means to change number is

constant it does not change and finally

we look for what's in control what

determines what so you can think through

the situation and off you go I hope this

video is helpful

keep working hard on your math you can

do it