Brad, a professor in the walton college of business, has taught data analysis for 3 years historically, during that time, his average grade is 70% with a standard deviation of 5%. he is disappointed in the results of his students and decides to try different teaching methods to improve their grades. in the spring of 2016, he develops on-line videos as a supplement to his class lecture. during that semester, his average grade is 71% from a sample of 49 students. the level of significance is 2.5%. what hypotheses is brad testing? 0 h0: μ .70 and ha: μ < .70 0 h0: μ s .71 and ha: μ > .71 0 h0: μ .70 and ha: μ > .70