Betropolis conducts an advertising campaign to get people to lose weight. A random sample of 49 people results in an average loss of 1 pound with a...

Betropolis conducts an advertising campaign to get people to lose weight. A random sample of 49 people results in an average loss of 1 pound with a sample standard deviation of 7 pounds. Can we infer that the campaign had an effect (good or bad) as opposed to no effect?