Help -normal distribution

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Help -normal distribution

newp
Hi , can any one help in this problem



According to some study, the height for Northern European adult males is
normally distributed with an average of 181 centimeter and a standard
deviation of 7.3 centimeter. Suppose such an adult male is randomly chosen.
Let X be height of that person. The next 3 questions correspond to this
information. The answer may be rounded up to 3 decimal places of the actual
value.





The middle 60% of heights fall between what two values??



Which R commands i should use to find answer?





Thanks.

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Re: Help -normal distribution

Arun.stat
try
qnorm(40/200)
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Re: Help -normal distribution

bbolker
In reply to this post by newp
n.a.s <nn.roh1 <at> gmail.com> writes:

>
> Hi , can any one help in this problem
>
> According to some study, the height for Northern European adult males is
> normally distributed with an average of 181 centimeter and a standard
> deviation of 7.3 centimeter. Suppose such an adult male is randomly chosen.
> Let X be height of that person. The next 3 questions correspond to this
> information. The answer may be rounded up to 3 decimal places of the actual
> value.
>
> The middle 60% of heights fall between what two values??
>
> Which R commands i should use to find answer?

  This looks an awful lot like homework [especially the "next 3 questions"
phrase ...].  Please note that the R list
is **not** intended for homework questions (primarily because
it's not fair to your teacher, who is probably expecting you to do your
work on your own, but also because we don't have time to do everyone's
homework for them).

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Re: Help -normal distribution

newp
In reply to this post by Arun.stat
Hi,

But i didn't understand why you did it like this qnorm(40/200)??

I already found the answer  qnorm(.20,181,7.3) and qnorm(.80,181,7.3)


Thanks.


On Mon, Aug 2, 2010 at 12:33 AM, Arun.stat <[hidden email]>wrote:

>
> try
> qnorm(40/200)
> --
> View this message in context:
> http://r.789695.n4.nabble.com/Help-normal-distribution-tp2309730p2309735.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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Re: Help -normal distribution

Arun.stat
I gave you hint only, however whatever you done is correct.



On Mon, Aug 2, 2010 at 4:30 AM, n.a.s <[hidden email]> wrote:

> Hi,
>
> But i didn't understand why you did it like this qnorm(40/200)??
>
> I already found the answer  qnorm(.20,181,7.3) and qnorm(.80,181,7.3)
>
>
> Thanks.
>
>
> On Mon, Aug 2, 2010 at 12:33 AM, Arun.stat <[hidden email]>
> wrote:
>>
>> try
>> qnorm(40/200)
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/Help-normal-distribution-tp2309730p2309735.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> [hidden email] mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>

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Re: Help -normal distribution

Joshua Wiley-2
Also note that you can 'switch' tails via the argument lower.tail.  By
default, it is TRUE.

> qnorm(p = .20, mean = 181, sd = 7.3, lower.tail = TRUE)
[1] 174.8562
> qnorm(p = .20, mean = 181, sd = 7.3, lower.tail = FALSE)
[1] 187.1438

Cheers,

Josh

On Sun, Aug 1, 2010 at 4:04 PM, Arun Kumar Saha
<[hidden email]> wrote:

> I gave you hint only, however whatever you done is correct.
>
>
>
> On Mon, Aug 2, 2010 at 4:30 AM, n.a.s <[hidden email]> wrote:
>> Hi,
>>
>> But i didn't understand why you did it like this qnorm(40/200)??
>>
>> I already found the answer  qnorm(.20,181,7.3) and qnorm(.80,181,7.3)
>>
>>
>> Thanks.
>>
>>
>> On Mon, Aug 2, 2010 at 12:33 AM, Arun.stat <[hidden email]>
>> wrote:
>>>
>>> try
>>> qnorm(40/200)
>>> --
>>> View this message in context:
>>> http://r.789695.n4.nabble.com/Help-normal-distribution-tp2309730p2309735.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
>>> ______________________________________________
>>> [hidden email] mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>>
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/

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