1. ## Norm Dist (excel)

Let X ~Normal(200, 60). Use Excel (Use the functions NORMDIST or NORMSINV, and fill in the dialogue box appropriately) to find the following.

k such that P(X>k)=0.01?

This is the only one giving me problems I use the normdist formula in excel and i enter the mean std deviation and the value (True/False) but I don't see how I can solve for a specific value, unless i just keep doing trial and error and i know this is not the right way to go about it.

thanks for any help.

2. You must simply ponder the defintions of the functions until it soaks in.

p(X>k) = 0.01 is the same as p(X<=k) = 0.99

=NORMSINV(0.99) gives 2.326348
Note: =NORMSINV(0.01) = -2.326348 and symmetry can be used to achieve the same result.

I'll let you fill in the last blank.

=NORMDIST(WhatGoesHere,200,60,1)

Figure out what the last "1" is, too.

3. I can't work out what goes there, but i get that the one is the same as writing true.

But I am lost.

I have another question and I think that I am supposed to use the same idea,

A machine fills bottles of soft drink to a mean volume of 510 ml with a standard deviation of 10 ml. Assume the the volumes of the bottles are normally distributed. The label on the bottle specifies a volume of 500ml.

What percentage of bottles is under-filled?

I have found this to be 0.158655

In order to reduce the percentage of under-filled bottles to 1%, the company decides to adjust the standard deviation of the volumes filled by the machine. What should the new standard deviation be?

Am I right in thinking that I am supposed to use the same process as in the first question?