Question 28 Suppose that the graduation rate in a school district is 85 percent. A random sample of students from the district are selected to participate in a mentoring program. Among this group of 100 students, 90 students graduate. The_ statistic for this hypothesis is reject the null at the 5-percent level of significance and in increasing graduation rates. therefore, you you conclude that the program is ot; 1.57; can; effective o Z; 2.80, can; effective t; 3.24; cannot; not effective o Z; 1.40; cannot; not effective Question 29 125 175 o 200 o 150 3 pts On a national achievement test with a population that is normally distributed with a population mean of 175 points and a population standard deviation of 50 points, Jo has a Z-score on this test of -0.5. What is her numerical score on this test? Question 30 3 pts o 24.45 to 35.55 o 27.94 to 32.06 28.04 to 31.96 o 25.87 to 34.13 3 pts Assume that the underlying population is normally distributed. Suppose that you have a random sample of 25 individuals with a sample mean of 30 and a sample variance of 100. The 95-percent confidence interval for the population mean is approximately: