# Chemical Forums

## Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: lonelinesspains on September 23, 2020, 06:08:53 AM

Title: Statistical Data Treatment and Evaluation Problem
Post by: lonelinesspains on September 23, 2020, 06:08:53 AM
Hi dear friends,
We used two methods to determine nitrate concentration in water, 3 repetition of measurements have been done in each method. Do the means in two methods differ significantly?
method A: 10, 10, 11 ppm
method B: 11, 11, 10 ppm
Degree of freedom (95%): 1       2      3        4       5         6
t: 12.7  4.30  3.18   2.78   2.57    2.45

Reference: Statistical Data Treatment and Evaluation, SKOOG
Title: Re: Statistical Data Treatment and Evaluation Problem
Post by: MOTOBALL on September 23, 2020, 10:51:43 AM
The rules of the forum require you to show your attempts at solving the problem, before we can provide any help.

Regards,
Motoball
Title: Re: Statistical Data Treatment and Evaluation Problem
Post by: lonelinesspains on September 23, 2020, 11:07:22 AM
Dear my friend,
I've tried to solve this problem before but already failed.
please give me the answer or at least some instructions to find solution.
thanks
Title: Re: Statistical Data Treatment and Evaluation Problem
Post by: billnotgatez on September 24, 2020, 12:13:19 AM
If you show what sort of understanding you have
From your class or textbook about statistics and what do you know about Degrees of freedom
Someone knowing your level of understanding may be able to give you hints

No one is allowed to just give you the answer
You have to show your attempts or thoughts at solving the question to receive help.
This is a forum policy.
Click on the link near the top center of the forum page.
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hint from the internet

Quote
The degrees of freedom in a statistical calculation represent how many values involved in a calculation have the freedom to vary. The degrees of freedom can be calculated to help ensure the statistical validity of chi-square tests, t-tests and even the more advanced f-tests.