Listed below are time intervals (min) between eruptions of a geyser. Assume that the "recent" times are within the past few years, the "past" times are from around 20 years ago, and that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Does it appear that the mean time interval has changed? Is the conclusion affected by whether the significance level is 0.10 or 0.01? Recent 77 91 90 78 56 99 62 88 71 88 83 83 56 80 75 103 62 Past 89 89 93 94 63 84 84 92 88 91 91 91 Let , be the recent times and let be the past times. What are the null and alternative hypotheses? A. Ho H = H H OC. Ho H =H2 H B. Ho H