In: Statistics and Probability
Assume that the differences are normally distributed. Complete parts (a) through (d) below.
| 
 Observation  | 
 1  | 
 2  | 
 3  | 
 4  | 
 5  | 
 6  | 
 7  | 
 8  | 
|
|---|---|---|---|---|---|---|---|---|---|
| 
 Xi  | 
 44.9  | 
 50.8  | 
 45.6  | 
 48.1  | 
 53.5  | 
 50.6  | 
 49.9  | 
 48.0  | 
|
| 
 Yi  | 
 46.2  | 
 51.3  | 
 48.9  | 
 52.8  | 
 53.7  | 
 52.8  | 
 50.3  | 
 50.6  | 
(a) Determine di=Xi−Yi for each pair of data.
| 
 Observation  | 
 1  | 
 2  | 
 3  | 
 4  | 
 5  | 
 6  | 
 7  | 
 8  | 
|---|---|---|---|---|---|---|---|---|
| 
 di  | 
 
  | 
(Type integers or decimals.)
(b) Compute d and sd.
(c) Test if μd <0 at the a=0.05 level of significance.
(d) Compute a 95% confidence interval about the population mean difference μd
Ans. (a)
| Obs. | Xi | Yi | di = Xi - Yi | di2 | 
| 1 | 44.9 | 46.2 | -1.3 | 1.69 | 
| 2 | 50.8 | 51.3 | -0.5 | 0.25 | 
| 3 | 45.6 | 48.9 | -3.3 | 10.89 | 
| 4 | 48.1 | 52.8 | -4.7 | 22.09 | 
| 5 | 53.5 | 53.7 | -0.2 | 0.04 | 
| 6 | 50.6 | 52.8 | -2.2 | 4.84 | 
| 7 | 49.9 | 50.3 | -0.4 | 0.16 | 
| 8 | 48 | 50.6 | -2.6 | 6.76 | 
| SUM = | -15.2 | 46.72 | 

