Preliminary data analyses indicate that you can reasonably use nonpooled t-proce
ID: 2955420 • Letter: P
Question
Preliminary data analyses indicate that you can reasonably use nonpooled t-procedures in Exercises 10.63-10.68. For each exercise, apply a nonpooled t-test to perform the required hypothesis test, using either the critical-value approach or the P-value approach. The seagrass Thalassia testudinum is an integral part of the Texas coastal ecosystem. Essential to the growth of T. testudinum is ammonium. Researchers K. Lee and K. Dunton of the Marine Science Institute of the University of Texas at Austin noticed that the seagrass beds in Corpus Christi Bay (CCB) were taller and thicker than those in Lower Laguna Madre (LLM). They compared the sediment ammonium concentrations in the two locations and published their findings in Marine Ecology Progress Series (Vol. 196, pp. 39-48). Following are the summary statistics on sediment ammonium concentrations, in micromoles, obtained by the researchers. At the 1% significance level, is there sufficient evidence to conclude that the mean sediment ammonium concentration in CCB exceeds that in LLM? In Exercises 10.69-10.74, apply Procedure 10.4 on page 512 to obtain the required confidence interval. Interpret your result in each case. Refer to Exercise 10.64 and determine a 98% confidence interval for the difference, mu 1 - mu 2 between the mean sediment ammonium concentrations in CCB and LLM.