The Sampling Distribution of a Sample Mean

Sampling Distribution of Difference Between Means

The mean of the distribution of the difference between sample means is equal to the difference between population means. $20 - 15 = 5$
The variance of the sampling distribution of the difference between means is equal to the variance of the sampling distribution of the mean for Pop $1$ plus the variance of the sampling distribution of the mean for Pop $2$ . $100/20 + 64/16 = 5 + 4 = 9$
Mean = $10$ , SD = $4$ , Plug these into the normal calculator and find the area above $6$ . You get. $841$ . A similar question using this data appears in the text.
Mean = $727 - 532$ = $195$ , Var = $12,000/12 + 10,000/14$ = $1,714.3$ , SD = $sqrt(1,714.3)$ = $41.404$ , Use the normal calculator to calculate the area above $150$ for a distribution with this mean and SD. You get $0.8614$ .