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All my effort to solve this two questions out of the assignments given to us was fruitless..pls I need your help sir's and ma's..
1) IN AN EXAMINATION THE AVERAGE GRADE WAS 74 AND THE STANDARD DEVIATION WAS 7. IF 12% OF THE CLASS ARE ALL GIVEN A'S AND THE GRADES ARE CURVED TO FOLLOW A NORMAL DISTRIBUTIONS. WHAT IS THE LOWEST POSSIBLE A'S AND THE HIGHEST POSSIBLE B'S?

2) A LOT CONTAIN 5 ITEMS OF WHICH 4 ARE EFFECTIVE, 3 ITEMS ARE DRAWN AT RANDOM FROM THE LOT ONE AFTER THE ONE WITHOUT REPLACEMENT, FIND THE PROBABILITY THAT ALL THE 3 ARE NOT EFFECTIVE?

GOD BLESS YOU AS YOU HELP A BROTHER....

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Danny4show:
All my effort to solve this two questions out of the assignments given to us was fruitless..pls I need your help sir's and ma's..
1) IN AN EXAMINATION THE AVERAGE GRADE WAS 74 AND THE STANDARD DEVIATION WAS 7. IF 12% OF THE CLASS ARE ALL GIVEN A'S AND THE GRADES ARE CURVED TO FOLLOW A NORMAL DISTRIBUTIONS. WHAT IS THE LOWEST POSSIBLE A'S AND THE HIGHEST POSSIBLE B'S?

2) A LOT CONTAIN 5 ITEMS OF WHICH 4 ARE EFFECTIVE, 3 ITEMS ARE DRAWN AT RANDOM FROM THE LOT ONE AFTER THE ONE WITHOUT REPLACEMENT, FIND THE PROBABILITY THAT ALL THE 3 ARE NOT EFFECTIVE?

GOD BLESS YOU AS YOU HELP A BROTHER....

*****Solution *****

Q2 given 4 effective , it means. 1 not effective

now total ways of selection = 5C3

p(not effective) = 1- p(effective)

=> 1 -[ 4C3/5C3 ] = 1-( 4/10)


hence probability that all three selected are not effective

I.e p(not effective) = 6/10 =0.6 that's it .

hope it helps ..

agentofchange1:
*****Solution *****

Q2 given 4 effective , it means. 1 not effective

now total ways of selection = 5C3

p(not effective) = 1- p(effective)

=> 1 -[ 4C3/5C3 ] = 1-( 4/10)


hence probability that all three selected are not effective

I.e p(not effective) = 6/10 =0.6 that's it .

hope it helps ..

yea thanks bro..what of the second question?