Question

The makers of the Oral-B 3D toothbrush claims that using their brush will "significantly combat tooth decay" when compared with regular toothbrushes. College students have an average of 0.70 (s = 0.40) cavities filled in a given year. You randomly ask 100 students to use the Oral-B 3D toothbrush for one year. They have an average of 0.631 cavities filled in that year. Does the Oral-B 3D toothbrush combat tooth decay at a significance level of .05? Complete a hypothesis test of this study that the using the Oral-B 3D toothbrush reduces (e.g., a "directional" hypothesis) tooth decay. Be sure to include all six steps of a hypothesis test.

USE Z Test.

Answer 1