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 78 91 89 78 58 99 62 87 70 89 82 84 56 81 75 101 61 Past 90 87 93 94 65 86 84 92 88 91 91 91

p value = 0.039

t = - 2.169

Step-by-step explanation:

Applying the null and alternate hypothesis

using excel worksheet to calculate for ( t and p )

t = -2.169

p = 0.039

from the results obtained

The conclusion is affected by the significance level because : 0.1 < p > 0.01

so when the significance level  is = 0.1 the Null hypothesis is rejected and we can say the mean time interval will change  while

if the significance level = 0.01 the Null hypothesis is accepted and we can not say the mean time interval has changed because the p -value is greater than 0.01

attached is the excel solution

d. is the correct answer

step-by-step explanation: