Next section**: **Linear combinations of means from independent groups

Summary of Computations

- Compute M
_{d}= M_{1}- M_{2 } - Compute SSE
_{1}= Σ(X - M_{1})² for Group 1 and SSE_{2}= Σ(X - M_{2 })² for Group 2

- Compute SSE = SSE
_{1}+ SSE_{2}

- Compute df = N - 2 where
N = n
_{1}+ n_{2}

- Compute MSE = SSE/df

- Find t from a t table.

- Compute

(If the sample sizes are equal then n_{h}= n_{1}= n_{2}).

- Compute:

- Lower limit = M
_{d}- t

- Upper limit = M
_{d}+ t

- Lower limit ≤ µ
_{1}- µ_{2}≤ Upper limit

- The populations each are normally distributed.

- Homogeneity
of variance

- Scores are sampled randomly and independently from 2 different populations

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