# Statistical Problem in Analytical Chem

1. Sep 16, 2011

### oxshannon

1. The problem statement, all variables and given/known data

The following set of analyses represent concentrations of chloride in blood serum (meq/L): 103,106,107,114. One value appears suspect. Determine if it can be rejected at the 95% confidence level.

2. Relevant equations
Mean

Standard Deviation:

http://www.sjsu.edu/faculty/gerstman/StatPrimer/t-table.pdf"

Degrees of Freedom = n -1 (n in this case being 4)

Confidence Interval:

3. The attempt at a solution

So I found the mean to 107.5, and the standard deviation to be 4.65 (If anyone wants to see how I did this, just let me know).

Then using the table, I found that t95 = 3.182 (using that there are 3 degrees of freedom)

Using the confidence interval formula, I calculated the answer to be 107.5 +/- 7.40.

I'm stuck from here and in fact have no idea if I even started this problem properly. PLEASE HELP :(

Last edited by a moderator: Apr 26, 2017
2. Sep 17, 2011

### oxshannon

Re: Chemistry Problem -- Analytical Chem

Anyone? :( I'm super desperate

3. Sep 17, 2011

### oxshannon

Re: Chemistry Problem -- Analytical Chem

Actually -- would it be possible to simply use Grubb's test?

Last edited: Sep 17, 2011