Statistics Normal Distribution

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Statistics Normal Distribution

Postby lora » Sat Apr 20, 2013 5:27 pm

Continuous Probability Distribution, Normal Distribution - IB Maths HL


How can we find the mean
of the weight of a population of students which is found to be normally distributed with standard deviation 2.5 Kg and the 20% of the students weigh at least 54 Kg.


Thanks
lora
 
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Re: Statistics Normal Distribution

Postby lily » Sat Apr 20, 2013 5:45 pm

Statistics Normal Distribution - IB Mathematics HL

Let the random variable denotes the weight of the students, so that



We know that

Since we don’t know the mean, we cannot use the inverse normal. Therefore we have to transform the random variable to that of

, using the transformation

we have the following





Using GDC Casio fx-9860G SD
MAIN MENU > STAT>DIST(F5)>NORM(F1)>InvN>

Setting Tail: right
Area: 0.2
:1
:0

We find that the standardized value is 0.84162123

Therefore






Hope these help!
lily
 
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Re: Statistics Normal Distribution

Postby lora » Sat Apr 20, 2013 6:26 pm

Thanks Lily!!
lora
 
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Joined: Wed Apr 10, 2013 7:36 pm


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