Twelve Dieters Lost an Average of 5 $- 1.8 < \mu _ { 1 } - \mu _ { 2 } < 0.4$

Multiple Choice

Twelve dieters lost an average of 5.2 pounds in 6 weeks when given a special diet plus a "fat-blocking" herbal formula. A control group of twelve other dieters were given the
Same diet, but without the herbal formula, and lost an average of 4.5 pounds during the
Same time. The standard deviation of the "fat-blocker" sample was 2.8 and the standard
Deviation of the control group was 2.5. Find the 95% confidence interval for the
Differences of the means.

A) $- 1.8 < \mu _ { 1 } - \mu _ { 2 } < 0.4$
B) $- 0.4 < \mu _ { 1 } - \mu _ { 2 } < 1.8$
C) $- 1.7 < \mu _ { 1 } - \mu _ { 2 } < 3.1$
D) $- 1.2 < \mu _ { 1 } - \mu _ { 2 } < 2.6$