the mean

[Hye]

A die was rolled 20 times with the following results:
Number of die
1
2
3
4
5
6

Frequency
2
5
3
2
4
4


The mode and mean respectively is 2 and 3.65.  How did they get 3.65 i got 3.5


thanks

[jasoN-]

[_avO]

just multiply each number by its frequency (i.e. 1x2 + 2x5 + ... 6x4) and divide by the total rolls (20) which gives you a mean of 3.65. Otherwise use the calculator.

[TrueTears]

(1*2+2*5+3*3+4*2+5*4+6*4)/(2+5+3+2+4+4) = 3.65


lol beaten twice ><

[Hye]

i used the calculator and it gave me 3.5 :S

[jasoN-]

sorry if you were using my answer i accidently typed 5*4 + 5*4 (answer yields 5.45) instead of 5*4 + 6*4, should be correct now

[TrueTears]

calc gives me 3.65 lol

[_avO]

What did you type in the calc Hye?

[_avO]

did you type in
L1, 1,2,3,4,5,6 and
L2 as 2,5,3,2,4,4?
Then did Calc - Two variable and got 3.5? Because that's not how you do it.

What you do is (after going into stats) you type out each number (1-6) and then repeat if it has more then 1 frequency. It should look something like this
1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6 then  
Calc - One variable, mean = 3.65

Refer to my post at the bottom

[VCE123456789]

thats so easy just cas it

[dec0da]

the wise and powerful calculator knows

[_avO]

But don't rely heavily on said calculator, as a simple miscalculation or pressing the wrong button can render a loss in marks!

[dec0da]

good point, but its not the calculators fault if the person puts the wrong data in, hehe

[_avO]

Just figured something out, if you have this type of question, plot both sets into list 1 and list 2 (frequency) and then hit Calc->One Variable and where it says frequency put it as list 2, and you should get your data instead of having to type out each number repeatedly!!

Edit: lol sad how I just figure it out, could have been useful for the SAC