# Thread: help newbie - problem

1. ## help newbie - problem

The standard deviation of the weight of filled salt containers is 0.4 ounce. If 2.5 percent of the container contains less than 16 ounces, what is the mean filling weight of the containers?

2. ## Re: help newbie - problem

It looks like your looking for a confidence interval of 97.5% is that right?

3. ## Re: help newbie - problem

To me it looks like there is a hidden assumption of normality that the OP didn't mention and the standard deviation of 0.4 is assumed to be the population standard deviation. You're also given one quantile and then the question is to figure out what the population mean is supposed to be.

My advice is to pretend like you were given the mean and the standard deviation and asked to figure out what percent of the container contains less than 16 ounces. You probably know how to do that problem. Backtrack from there to figure out what the mean is given that you know what that percentage is.

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