S1 and S2 DOUBTS HERE!!!!

[~ Miss Relina ~]

Yes and it will definitetely curve as nutters practice 168 hours a week and make less than zero mistakes

yes Thanks alot Sir 

[silvercameron]

thankyou sir, i got how to do it.
But could you pls answer my other question?

[astarmathsandphysics]

Is that the quantiles question?
http://www.astarmathsandphysics.com/a_level_maths_notes/S1/a_level_maths_notes_s1_quartiles_and_median_from_frequency_tables.html

[silvercameron]

no sir. I am sorry but this isnt exactly my doubt. I wanted to know how we find the quartiles for large data with no classes.
For example:

Score          :     0       1         2       3       4      5      6
frequency :   36      94     48     15     7      3      1

[astarmathsandphysics]

For this one, there are 36+94+48+15+7+3+1=214
I would do this:214/4=53.5 so the lower quartile is 1
For the upper quartile find 3/4*215=160.5 so the upper quartile is 2
More complicated methods exist but for S1 do as above..

[silvercameron]

thankyou,sir.oh, but my i already know about this method, but when solving some questions like this, i sometimes get the wrong answer.

[astarmathsandphysics]

Give examples. This method is for Edexcel.

[silvercameron]

A question:
An ordinary dice was thrown 50 times and the resulting scores were summarised in a frequency table. The mean score was calculated to be 3.42. It was later found that the frequencies 12 and 9,of two consecutive scores,had been swapped. What is the correct value of the mean?

[astarmathsandphysics]

differene of12n+9(n-1)-12(n-1)-9n==12-9=3
3/50=0.06
3.42+0.06=3.48
or 3.42-0.06=3.36

[Sea Lover]

can somone help me with these two questions:
1-Three letters are selected at random from the word SCHOOL.Find the probablity that the selection:
a)does not contain the letter O
b)contains both letters O

2-In how many different ways can a football team of 11 players be photographed if there are to be two rows ,with 5 seated on the front row and 6 standing in the back row?In how many of these photographswould the captain be sitting in the centre of the front row?
thanx in adavnce

[astarmathsandphysics]

1a.4/6*3/5=12/30=2/5
b.2/6*1/5=1/15

2.11! cos each player is an individual and they can be told apart.
The captain can sit on the front in one of five places and the others can arrange themselves in 10! ways so5*10!

[~ Miss Relina ~]

1a.4/6*3/5=12/30=2/5
b.2/6*1/5=1/15

2.11! cos each player is an individual and they can be told apart.
The captain can sit on the front in one of five places and the others can arrange themselves in 10! ways so5*10!

Sir why how did you find the first answer why did you mulitply 4/6 * 3/5 ...

[astarmathsandphysics]

cos there are four non 'o' letters out of 6 so prob of not picking o is 4/6
when this letter is picked, there are three non 'o' letters out of five, so prob of picking non 'o' letter is 3/5
then 4/6*3/5

[astarmathsandphysics]

theeducationchannel.info is working now. You can also ask for a 'video solution'

[~ Miss Relina ~]

cos there are four non 'o' letters out of 6 so prob of not picking o is 4/6
when this letter is picked, there are three non 'o' letters out of five, so prob of picking non 'o' letter is 3/5
then 4/6*3/5

but that's with assuming that the number is not replaced ......right ok if that's the case then it might me 4/6*3/5*2/4 as he picked three numbers right

Thanks for the link I'll try it