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Mathematics: Post your doubts here!

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Salaam Alaykum, Please help:
Esme noted the test mark, x, of 16 people in a class, she found that Σ x= 824 and that the standard deviation of x was 6.5
i) Calculate Σ (x-50) and Σ (x-50)²
ii) One person did the test earlier and her mark was 72. Calculate her new mean and standard deviation of the marks of all 17 people.


Thanks in advance Ali Railey
 
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Salaam Alaykum, Please help:
Esme noted the test mark, x, of 16 people in a class, she found that Σ x= 824 and that the standard deviation of x was 6.5
i) Calculate Σ (x-50) and Σ (x-50)²
ii) One person did the test earlier and her mark was 72. Calculate her new mean and standard deviation of the marks of all 17 people.
Thanks in advance Ali Railey

"Esme" :p :D

Sorry for the useless post...
 
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abt the Greengage one not 100% sure but its like this
*R*E*E*N(GG)A*E* if you consider both g's as 1 then there is 7 letters and the starts as places where the g's can be then there are 7 slots since in one slot the 3rd g will be placed in the other gg's got 6 slots so its 7!*6/3!(for the eees)
 
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abt the Greengage one not 100% sure but its like this
*R*E*E*N(GG)A*E* if you consider both g's as 1 then there is 7 letters and the starts as places where the g's can be then there are 7 slots since in one slot the 3rd g will be placed in the other gg's got 6 slots so its 7!*6/3!(for the eees)
But what about other G ? :eek:

And other question?
 
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When do we take values of
eg.

P(X < k) = 0.7465

When will we take

phi(k) = 0.7465

and how will we know that if its correct of we should use.

1 - phi(k) = 0.7465
 
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When do we take values of
eg.

P(X < k) = 0.7465

When will we take

phi(k) = 0.7465

and how will we know that if its correct of we should use.

1 - phi(k) = 0.7465


assalam walaikum
brother... if it is phi(-k)=0.7465
according to the rule phi(-k)= 1- phi(k)
hope that helps
 
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Salaam Alaykum, Please help:
Esme noted the test mark, x, of 16 people in a class, she found that Σ x= 824 and that the standard deviation of x was 6.5
i) Calculate Σ (x-50) and Σ (x-50)²
ii) One person did the test earlier and her mark was 72. Calculate her new mean and standard deviation of the marks of all 17 people.
Thanks in advance Ali Railey

s1.jpg
 
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