ShmoopTube

00:04

Here's your shmoop du jour brought to you by honey and the age-old [People sitting in chairs with Winnie the Pooh]

00:07

question when will Pooh finally admit he has a problem and here's the question

00:13

Sally conducted an experiment to determine if eating peanut butter and

00:17

honey ahead of a math exam led to better scores she found an honors algebra class

00:21

and discovered that the algebra students who ate more peanut butter and honey

00:24

received an average of 93 while the students who ate less peanut butter and

00:29

honey scored 86, this relationship is called a what

00:34

well let's start with A symmetric [Pooh writing on chalkboard]

00:41

distribution describes a statistical situation in which the values of

00:45

variables occur at regular frequencies like bell curves... If Sally had found that

00:51

both too much and too little peanut butter and honey led to identical grades [Sally with a bell curve]

00:55

and there was a perfect amount of peanut butter and honey that provided optimal

01:00

grades then this would be our answer but unfortunately for us there's not really [Pooh with peanut butter and honey]

01:05

such thing as the perfect amount of peanut butter and honey we always end up

01:08

wanting more what about B? Well a variance is the difference between a

01:13

projected value and the actual result a positive variance would be when the

01:17

result exceeds the expectation for instance a positive budget variance

01:23

would be when the expenses are less than predicted leading to a positive end [Girl with a dollar bill]

01:27

amount like if you bought two bathtubs full of peanut butter and honey would

01:31

cost a thousand bucks but it only ended up costing you 850 [Two bath tubs filled with peanut butter and honey]

01:35

okay sure we might have a problem how about C? Standard deviation is a measure

01:40

used to quantify the amount of variation within a set of values, well for

01:44

standard deviation of the test grades was a high number it would mean that [Student holding up test grades]

01:48

most student test scores vary greatly however if the number was close to zero

01:52

it would mean most people have very similar test scores, well this could

01:56

definitely apply to Sally's experiment it has nothing to do with the scores as

02:00

they relate to peanut butter and honey consumption negative correlation is [Sally with peanut butter and honey in the kitchen]

02:03

close but no cigar the word correlation does directly describe the relationship

02:10

between two variables, however the word negative is where we

02:13

part ways with E - In this context negative describes when two variables

02:18

travel in opposite directions of one another [Variables moving in opposite directions]

02:20

if grades went down as the peanut butter and honey consumption went up, then we'd

02:25

have a negative correlation however we know that's not the case in fact

02:29

it's the opposite as the consumption goes up so to goes grades - so we're

02:34

looking for the opposite of negative you wonder what that could be..... [Teacher marking out answers on board]

02:39

So it's D - positive correlation that's our answer

02:42

a positive correlation is when both sets of values increase simultaneously making

02:47

the relationship a positive one sounds pretty sweet to us...[Pooh with a jar of honey]

Full Transcript