A sportswriter wished to see if a football filled with helium travels farther, on average, than a football filled with air. To test this, the writer used 18 adult male volunteers. These volunteers were randomly divided into two groups of nine participants each. Group 1 kicked a football filled with helium to the recommended pressure. Group 2 kicked a football filled with air to the recommended pressure. The mean yardage for group 1 was= 30 yards with a standard deviations₁= 8 yards. The mean yardage for group 2 was= 26 yards with a standard deviations₂= 6 yards. Assume the two groups of kicks are independent. Let₁and₂represent the mean yardage we would observe for the entire population represented by the volunteers if all members of this population kicked, respectively, a helium-filled and an air-filled football. Assume that two sampletprocedures are safe to use.

Based on the 99% confidence interval for₁-₂, the sportswriter should conclude that there is:

A) statistically significant evidence at a 1% significance level that, on average, footballs filled with helium will travel farther when kicked than footballs filled with air.

B) statistically significant evidence at a 1% significance level that, on average, footballs filled with helium will travel the same distance when kicked as footballs filled with air.

C) statistically significant evidence at a 1% significance level that, on average, footballs filled with air will travel farther when kicked than footballs filled with helium.

D)no statistically significant evidence, at a 1% significance level, of any difference in the average distance that footballs filled with helium and footballs filled with air will travel when kicked.