View Full Version : Normally Distributed Data w/ mean of 16, standard dev. of...

Jen123

04-27-2008, 03:49 PM

Question: A set of data is normally distributed with a mean of 16 and a standard deviation of 0.3. What percent of the data is between 15.2 and 16?

So far I got: I wrote the limits in terms of the mean: 16 - 0.8 = 15.2 and 16 - 0 = 16.

Then I solved for t: t(0.3)= 0.8, t=2.67 which equals 99.3%.

This was a test question I got it wrong but I'm not sure where I went wrong because I tried to follow the book and I continue to get the same answer.

Subhotosh Khan

04-27-2008, 03:53 PM

Question: A set of data is normally distributed with a mean of 16 and a standard deviation of 0.3. What percent of the data is between 15.2 and 16?

So far I got: I wrote the limits in terms of the mean: 16 - 0.8 = 15.2 and 16 - 0 = 16.

Then I solved for t: t(0.3)= 0.8, t=2.67 which equals 99.3%.

This was a test question I got it wrong but I'm not sure where I went wrong because I tried to follow the book and I continue to get the same answer.

Look at z-distribution table:

z\, = \, \frac {x\, - \, \mu}{\sigma}

Jen123

04-27-2008, 04:27 PM

I looked in my book for a z distribution table and i could not find it could you explain yourself a little more and identify your variables please I'm confused.

Thanks

stapel

04-27-2008, 04:36 PM

Look at z-distribution table:

z\, = \, \frac {x\, - \, \mu}{\sigma}

I looked in my book for a z distribution table and i could not find it could you explain yourself a little more and identify your variables please

How on earth is your statistics course discussing "distributions" and "normality", if it hasn't yet covered the concepts of (and variables for) "mean" and "deviation", and has no information on z-tables...? :shock:

Eliz.

Jen123

04-28-2008, 12:07 AM

I don't have a teacher, so I haven't discussed it with anyone. I just have a book and in the book it has nothing referring to a z table thats why I asked for further help. I still need the help of figuring out how to solve the problem the correct way, or could someone explain solving it with a z table.

stapel

04-28-2008, 07:18 AM

I don't have a teacher.... I just have a book and in the book it has nothing referring to a z table.... could someone explain solving it with a z table.

Unfortunately, we are not able to teach courses within this environment. Since the various lessons you've found online (to supplement your apparently quite odd book) have not been sufficiently helpful, it may be time to consider taking a class, or hiring a tutor, in order to obtain the hours of instruction you have requested.

My best wishes to you in your studies! :D

Eliz.

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