The overall distance traveled by a golf ball is tested by hitting the ball with iron byron, a mechanical golfer with a swing that is said to emulate the legendary champion, byron nelson. ten randomly selected balls of two brands are tested and the overall distance measured. assume that the variances are equal. the data follow: brand 1: 288 278 287 271 283 271 279 275 263 267 brand 2: 261 238 260 265 273 281 271 270 263 268 (a) is there evidence to show that there is a difference in the mean overall distance of brands? use (b) calculate a 95% two-sided confidence interval on the difference in mean overall distance. round your answer to one decimal place (e. g. 98.7