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AP Statistics 2.1 Exploring Data
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AP Statistics 2.1 Exploring Data. How does this change affect the mean, standard deviation, and IQR?

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AP Statistics 5.2 Exploring Data. Which method would not be a good option?

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AP Statistics 2.1 Exploring Data 210 Views


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AP Statistics 2.1 Exploring Data. How does this change affect the mean, standard deviation, and IQR?

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Transcript

00:04

And here's your shmoop du jour brought to you by pop quizzes the only [Boy blindfolded testing fizzy drinks]

00:07

real way to test whether someone knows their coke from their pepsi alright quiz

00:11

scores this quarter we're kind of low and your teacher decides to add five

00:15

points to everyone's individual quiz grades how does this change the mean,

00:19

standard deviation and interquartile range for the classes quiz scores. Huh,

00:26

and here the potential answers....Okay this is a three-in-one deal pretty nice [Jacobs 3-in-1 coffee packet]

00:33

when opening a peanut but not nearly as exciting when in the form of a math

00:37

problem anyway let's just divide and conquer the first thing we need to [A knight wielding a sword]

00:41

figure out is how the mean will be affected if everyone score gets five

00:46

points tacked on to it plus reminder the mean is the same as the average so now

00:52

we're just adding five points to a score or two well the average would definitely [teacher marking papers]

00:57

be affected. But since every student is getting five bonus points across the

01:01

board the mean goes up by 5 too. Although if you ask us it's not much of a bonus if [Boy in a suit throwing cash into the air]

01:07

everyone gets one we don't want to raise, if everyone gets a raise like maybe

01:11

we're too competitive for our own good so yeah imagine three people get scores of one

01:15

two and three the mean of those scores is 1 + 2 + 3 divided by 3 or 2.. Add 5 to

01:22

each of those scores and we get six seven eight the mean of those scores is

01:26

six plus seven plus 8 divided by 3 or seven! exactly five higher alright well now that we've

01:31

confirmed that tid bit of information well looks like we can kick answers D

01:35

and E to the curb we're asked next about that standard deviation but before we [magnifying glass inspecting the question]

01:40

start whipping out a formula or two let's think about this for a skinny

01:43

minute the standard deviation is about how spread out the data are from each [example of a standard deviation formula]

01:48

other well since each score is being affected in exactly the same way plus [teacher throws number into the air]

01:53

five to each the scores aren't any further apart from each other than

01:57

before so the standard deviation will stay the same kind of likes Beyonce [Two beyonces wearing sparkling dresses]

02:02

seriously she hasn't changed in 15 years what is her secret? Now the only one of

02:07

our three remaining choices that shows a standard

02:09

deviation remaining the same is answer C so it looks like that's our horse but [A horse sniggering]

02:14

let's double check the interquartile range too just to be sure. Well to find

02:18

the interquartile range we have to subtract the value of Q 1 the first

02:22

quartile from q3 the third quartile well since both of these scores will have had [Q1 substracted from Q3 value]

02:28

five points added to them we're going to subtract five from five and those new

02:33

points are going to cancel out completely meaning the interquartile

02:37

range won't change a lick either which is still in line with option C and [Option C ticked green]

02:41

that's going to be our answer whoa, we've got another three in one who exactly his

02:45

growing these mutant peanuts [Man with 3 heads growing peanuts]

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