Question

Class A Class B Class C
80 72 100
85 90 90
87 85 94
92 84 100
86 91 75
90 78 30
94 94 94
100 86 72
75 82 85
45 78 87
85 86 42
38 78 100
72 95 90
94 90 94
62 88 60
Question 1

Analyze the data for Class A and Class B.

Part 1: What are the means and standard deviations for Classes A and B?
Part 2: Make a box plot of the data for Classes A and B. Identify the median, first and third quartiles, and minimum and maximum data points.
Part 3: Explain how the values for Classes A and B vary about the mean and median. What information does this give Mrs. Smith?

Answer 1

The mean for class A is 79

Answer 2

Remember, To find to mean, you just add all the numbers together, and then you divide the sum of those numbers, by the number of integers you have.

Answer 3

?

Answer 4

80 + 85 + 87 + 92 + 86 + 90 + 94 + 100 + 75 + 45 + 85 + 38 + 72 + 94 + 62 = ____

Answer 5

I want you to add those numbers together and tell me what you get

Answer 6

OK

Answer 7

1,185

Answer 8

great! now we need to divide, how many numbers do we have here? 80, 85, 87, 92, 86, 90, 94, 100, 75, 45, 85, 38, 72, 94, 62

Answer 9

? what does that mean ? and thanks for all you help

Answer 10

so i divide by 15 ?

Answer 11

okay, we have 15 numbers here..

Answer 12

so now, to find the mean, we will need to divide 1,185 by 15

Answer 13

79

Answer 14

there you go! 79 is the mean

Answer 15

but now you need to find the mean for class B

Answer 16

ok ik how do that know what about what about part 2 and many thanks i love you men not even my teacher makes it that easy

Answer 17

Box plot, hmm, thats a bit hard for me to do, one second let me try to bring someone else in here

Answer 18

@ganeshie8 @Hero @ParthKohli

Answer 19

omg thank men your the best thanks for teaching me and not just giving me the answer

Answer 20

Lol your welcome, and btw im a girl :)

Answer 21

one moment, somebody should be coming to help out

Answer 22

what ever i still love you lol hey i gat 85.133333 for b ? far part 1 ?

Answer 23

um, one second let me see if that is correct

Answer 24

You are correct, now you just turn it to 85.13

Answer 25

79 - Class A 85.13 - Class B

That's it for part 1

Answer 26

I am going to bring somebody in so I can better assist you, one minute

Answer 27

@phi @ParthKohli @jigglypuff314 @KingGeorge

Answer 28

ok

Answer 29

@mathmale

Answer 30

Part 2? need to make a box plot..

Answer 31

ok

Answer 32

i never learned box plots either, so idk how to do part 2,

Answer 33

how bout you ask some of the people you are fans of for help?

Answer 34

@SolomonZelman

Answer 35

i asked :/

Answer 36

i am asking a bunch of people who are online and not one of them came, lol

Answer 37

did you get how to work out the standard deviation for each column?

Answer 38

are you allowed to use a spreadsheet or calculator?
or do you have to show the working out?

Answer 39

yes

Answer 40

@SolomonZelman

Answer 41

btw im home and i just need help in a only class

Answer 42

help not answers

Answer 43

its a bit of a pain to calculate standard deviations.. you can either put all the numbers into a spreadsheet, and then ask it to calculate it for you.. or you do it manually.. you have to subtract the mean from every value one at a time.. and then you take each result and square it..

Answer 44

honestly i just need help :/

Answer 45

then you add them all up.. and divide by either (the count of all the results) or (the count of all results - 1) just like you calculated the mean.

Answer 46

i dont know here you gat -1 from

Answer 47

you then take the square root of that value. and that is the standard deviation..

why would you use (the count of all the results -1) OR just (the count of all the results)?

Answer 48

good thing you asked :) 1 sec.. explanation ...

Answer 49

There are two main ways to calculate standard deviation: population standard deviation and sample standard deviation.

Population : This is the equation for population standard deviation, which is used when all values of a population are known.

Sample: This is the equation when only SOME of the values of a population are known.

Answer 50

English plz lol

Answer 51

if using sample equation.. then we add -1

Let's just forget -1 ... and say we have population formula.. and assume that all data points are known.

Answer 52

sorry to confuse.. but you will likely run into this

Answer 53

its ok thanks

Answer 54

so subtract the mean from every number.
square each result
add all the results together
divide by the count of the total number of results
take the square root of that result
you now have the standard deviation

Answer 55

I would use a spreadsheet for this stuff.. like google spreadsheet under google Drive and Apps.

Answer 56

you just enter all the values.. and then use the =stdev(RANGE) function

Answer 57

purple math might help explain the box and whisker plot.. and using a spreadsheet will make it easy to order the values.. you just tell it to sort..
http://www.purplemath.com/modules/boxwhisk.htm

Answer 58

do you have any experience with spreadsheets? They're really good at operating on a range of data.. you can lay data out on a table, and select whole ranges and operate on them.. for example to get the mean you can just enter into a cell "=average(a1:a5) and it would return the mean average of the cells labelled a1 to a5... its worth playing around with one for these types of problems.

Answer 59

um let me try