## Observational Study vs Experiment

so what's the difference between an

observational study and an experiment

it's a pretty significant difference

actually the difference between

observational study in an experiment is

that in an observational study the

researcher does not influence the

responses in any way they just stand

around and watch whereas in an

experiment the researcher deliberately

applies a treatment before observing any

of the responses so let me give you an

example here and an observational study

say I wanted to do a statistical study

on cars driving habits of people when

they come to a yellow light and I stand

off to the side and I'm just watching to

see what the cars are doing so the first

car comes by and it's a yellow light and

they stop and then once it turns green

they move on and I record what happens

and then the next car comes by and it

turns into a yellow light and this car

speeds up and goes through the light

because they're in such a hurry and then

I watch the next car and it's another

one and it turns yellow and wood speeds

through because it needs to get going as

well and the last car that I observe

turns into a yellow light and it

actually slows down and stops weights

and then once the light turns green it

moves on as well so in that case all I'm

doing is just watching I'm observing to

see what the cars and the or I should

say what the drivers are doing now how

can they turn this whole thing into an

experiment well instead of me just

standing around watching what if I stand

right next to the light

right on the corner and in my hand I

have a radar gun I'm going to write this

on there this is a radar gun right here

so I am standing here where the drivers

can see me and I have just applied a

treatment the treatment in this case

would be seeing the radar gun we want to

see how drivers react to a yellow light

when there is a radar gun a person

standing with the radar gun right next

to the yellow light that they're coming

up on so in this case the first car

comes by and they see the radar gun and

they stop and the next light comes by

light turns green and they go through

the next one comes by and this cars

coming uh-oh he sees the radar gun and

he stops as well and then the light

turns green and they move on the next

car is speeding up and then Oh

radar gun makes them stop as well and

then it turns green and they move on and

then there's another car here and

they're speeding up and it turns yellow

and they just go ahead and speed through

the light anyways so that's the main

difference between an observational

study in an experiment and the first

case I was just watching to see what

happens and what I was doing did not

influence what the drivers would do

whereas in the second example that would

be an experiment because I am applying a

treatment in this case seeing the radar

gun is the treatment and how once I see

how the drivers react not only am i

watching what they do but I'm applying

this treatment so

that I can see how the treatment affects

their driving habits