Question

Statistic u_u

Answer 1

Do you know which part is wrong?

Answer 2

I tried to being by find the min and max, I got 0 and 9 for for # of students, then Q1 and Q3 to find the IQR and finally the standard deviation

Answer 3

I failed finding the max ._. It says 20 so I assume they're talking about the hours?

Answer 4

Not sure

Answer 5

I think your high and low are correct

Answer 6

I found a few typo's before so I'm not sure either ;_; I didn't want to go into my exam until I understood why I got it wrong .___. *facepalm*

Answer 7

After I finish part I have have another 2 parts, would you like to see them?

Answer 8

What is IQR?

Answer 9

The Interquartile range (IQR), the middle half of the data; it's a measure of how widely the middle half of the data is spread around the median :3

Answer 10

Okay, so you need to find the median and quartile points?

Answer 11

I tried starting off like that, but Idk where I failed

Answer 12

I don't know if this is any of use, I found it to give me a clue :l

Answer 13

of any use *

Answer 14

I already knew that much.

Answer 15

It think it is just a matter of not calculating it correctly.

Answer 16

Okay, first, do you know the total number of students?

Answer 17

>.> They said that using geogebra to make it easier to graph, I wanted to find the points first to then plot it in geogebra. I see there's 42 students in grade 11

Answer 18

what kind of graph?

Answer 19

They used for example a histogram

Answer 20

Wio? ;_;

Answer 21

I'm doing some calculations on my own right now

Answer 22

Oh ok! Does that mean your doing your own calculations or calculations related to this problem?

Answer 23

calcs for this problem

Answer 24

O.O i didn't think it would be this difficult tbh u.u

Answer 25

I think they're talking about the hours (not students)

Answer 26

Yea i kinda figured the same thing when I saw the max was 20, though how did they get that Q1 and Q3 though

Answer 27

So Q2 is median, right?

Answer 28

Yes, normally the q2 is found my subtract q3 - q1

Answer 29

Grade 11:
there are 42 student. The median is between the 21st and 22nd value.
so (3+3)/2 = 3

Answer 30

21st and 22nd? where did you get that?

Answer 31

from listing the hours with their respective frequency from smallest to largest
{0,0,0,0,0,0,0,1,1,1,...}
21st = 3
22 = 3

Q1 is the 11th value which is 2

Answer 32

*22nd = 3*

Answer 33

I didn't understand how to do the {#######}

Could you explain it?

Answer 34

http://jsfiddle.net/wio_dude/B94HF/

My calculations so far. I'm going to try to get quartile 1 and 2 next.

Answer 35

well you just list the numbers. 7 students spent 0 hours. So,
{0,0,0,0,0,0,0,...}

3 students spend 1 hours,
{0,0,0,0,0,0,0,1,1,1,...}
and so on

Answer 36

Ohhhh :o

Answer 37

Q3 is the 32th value, which is 5

Answer 38

IQR = 5-2 = 3

Answer 39

Oh so it was right >.< sorry for wasting your time Wio / Sourwing :P

Ty :*

Answer 40

How did you get 32th value?

Answer 41

half way between 22nd and 42th is (22+42)/2 = 32

Answer 42

@tHe_FiZiCx99 i assume you know how to find mean and standard deviation.

Good luck on your exam :)

Answer 43

I do, http://prntscr.com/2qtjz8

Ty!!

Answer 44

http://jsfiddle.net/wio_dude/B94HF/
This is what I am getting.

Answer 45

Luis, sorry to throw a rock into your machinery, but that formula for std. dev. is not quite correct. That summation symbol (sigma) goes in front of (x-mean)^2 and on the same level (line); it does NOT go in front of the fraction [(x-mean]^2/n]. Hope this makes sense. Verify what I've said here; do another internet search for "standard deviation."

Answer 46

Please see:

http://www.mathsisfun.com/data/standard-deviation-formulas.html

and note that (1/n) is in front of the SUMMATION of (x-mean)^2.

Answer 47

It says in my lesson that: http://prntscr.com/2qua2h

Answer 48

Must be maddening when your lesson says one thing and your so-called teacher tells you another thing. Try both formulas and see which one produces the answer you were expecting. If you have any problem with this still, contact me about it tomorrow and we'll go thru it again. OK?

Answer 49

Sure!! Thanks! :)

Answer 50

Wouldn't want to argue with you! But sometimes I get a kick out of asserting that I'm right. :)

Answer 51

So do I :o

Answer 52

http://prntscr.com/2qucz4

*facepalm*

Answer 53

that's wrong. The first half of the set has 21 datas. I.e from 1 to 21.
You only include 1 to 20

Answer 54

[1 - 21] Q2 [22 to 42]

Answer 55

So, I would find 21 - 21 each side?

Answer 56

yes, each side has 21 datas

Answer 57

Now what is half way between 1 and 21?

Answer 58

10.5 ?

Answer 59

*gets it wrong* ;_;

Answer 60

no, (1 + 21)/2 = 11

it's the 11th spot

Answer 61

Omg i had 11 ._. counted only 21 though u.u

Ok so 22 + 22 = 42

42 being the original. So I would find the middle, sooo i got 2 as q1

Answer 62

yep :)

Answer 63

\(\color{blue}{\text{Originally Posted by}}\) @mathmale
Luis, sorry to throw a rock into your machinery, but that formula for std. dev. is not quite correct. That summation symbol (sigma) goes in front of (x-mean)^2 and on the same level (line); it does NOT go in front of the fraction [(x-mean]^2/n]. Hope this makes sense. Verify what I've said here; do another internet search for "standard deviation."
\(\color{blue}{\text{End of Quote}}\)
What are you rambling about?\[
\sum_{i}^{N} cf(i)= c\sum_{i}^{N} f(i)
\]Let \(c=1/N\):
\[
\sum_{i}^{N} \frac{f(i)}{N} = \frac{1}{N}\sum_{i}^{N} f(i)
\]They are the same formula.

Answer 64

I just see random letters now ._.

Answer 65

latex probably isn't working on your computer :D

Answer 66

No no, http://prntscr.com/2qufrc >.>

Answer 67

btw, the standard deviation you provided is still correct. MathMale probably got it confused because the sigma is right infront of the division bar

Answer 68

I got Q1 = 2 and Q3 = 5

Answer 69

yes

Answer 70

:O

Answer 71

??

Answer 72

So Q2 = 3 ;O

So now that I have:

Max = 20
Low = 0
Q1 = 2
IQR = 3
Q3 = 5

I can find the Standard Deviation. :p

I'll do the same process for Grade 12 :P

Ty everyone! :*

Answer 73

yw

Answer 74

:>