1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Null Hypothesis Waterbody - Environmental Statistics

  1. Apr 5, 2013 #1
    1. The problem statement, all variables and given/known data

    Past study in a contaminated waterbody has revealed that the percentage contamination level of the surface water has been determined at 24.75%

    a)Based on a study of a random sample of 40 containers of the same size, it is observed that the sample percentage of contaminted containers is 21.65%. Does it indicate that some efforts have gone into cleaning of the waterbody?

    b)An independant organization conducted a similar parallel study at it revealed that the percentage contaminatin level was 22.78% based on a sample size of 25. Does this corroborate the decision reached in question A.

    c)Can you combine the two data sets and come up with a bettter understanding about the level of contamination of the waterbody.

    2. Relevant equations

    I believe we use P +/- 1.645 sqrt((P(1-P)/n) with a confidence level of 95%

    3. The attempt at a solution

    See attached pdf . Does anyone see any issues with my calculations? Just realized my 95% CI z value should be 1.645 not 1.654. Other than that, any issues?

    Attached Files:

  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted

Similar Threads - Null Hypothesis Waterbody Date
Write a matrix given the null space Jan 30, 2017
A real parameter guaranteeing subspace invariance Nov 4, 2016
Vector space property Oct 3, 2016
Null solutions Jun 12, 2016
Statistics: Statistical Significance and Null Hypothesis Feb 16, 2006