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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

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
**Posts:**0**Joined:**Wed Apr 10, 2013 7:36 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!

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
**Posts:**0**Joined:**Mon Jan 28, 2013 8:04 pm

3 posts
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