Stats Problem?
Question:
Answers:
H0 : The guideline is reasonable (that is to say, same ratios still apply, or ABC = CBS = NBC = 30 %, rest = 10 % )
H1: The guideline is not reasonable (the ratios do not apply)
Use the Chi square test (χ^2). Why? Check your textbooks. :) Sample values are:
ABC = 165
CBS = 140
NBC = 125
rest = 70
Expected values (if the given ratios still stand)
ABC = 30 % * 500 = 150
CBS = 30 % * 500 = 150
NBC = 30 % * 500 = 150
rest = 10 % * 500 = 50
df = 4 - 1 = 3 (where df stands for degrees of freedom, and 4 stands for the number of stations)
Using this formula:
http://www.sixsigmafirst.com/chi_square_...
calculate the value of χ^2. fi are the values you obtained from the sample (165, 140, 120, 70), and f'i are expected values.
You can obtain the critical value of χ^2 for 3 degrees of freedom and α = 0.05 from the tables for χ^2 distribution (my tables say it's 7.815). After you've found it, compare it to the calculated value of χ^2.
If the calculated value of χ^2 is lower than the table value, H0 stands. If not, you could say that, with confidence of 0.95, we claim the guidelines to be untrue.
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