Confidence Interval on Difference Between Means, Independent Groups, Standard Deviation Estimated (7 of 7)

previous




Summary of Computations

  1. Compute Md = M1 - M2

  2. Compute SSE1 = Σ(X - M1 )² for Group 1 and SSE2 = Σ(X - M2 )² for Group 2

  3. Compute SSE = SSE1 + SSE2

  4. Compute df = N - 2 where N = n1 + n2

  5. Compute MSE = SSE/df

  6. Find t from a t table.

  7. Compute



    (If the sample sizes are equal then nh = n1 = n2).

  8. Compute:



  9. Lower limit = Md - t

  10. Upper limit = Md + t

  11. Lower limit  ≤ µ1- µ2 ≤  Upper limit


Assumptions:
  1. The populations each are normally distributed.

  2. Homogeneity of variance

  3. Scores are sampled randomly and independently from 2 different populations



previous