Answer Happy

An article in Polymer Degradation and Stability (2006, Vol. 91) presented data from a nine-year aging study on $537 foam. Foam samples were compressed to 50% of their original thickness and stored at different temperatures for nine years. At the start of the experiment as well as during each year, sample thickness was measured, and the thicknesses of the nine samples at each storage condition were recorded. The data for two storage conditions follow.
(a) Is there evidence to support the claim that mean compression increases with the temperature at the storage condition? Assume that the variances are equal. Use α=0.05. Suppose that the hypotheses are H0​:μ1​−μ2​=0 versus H1​:μ1​−μ2​<0, where 1 indicates the storage at 50∘C and 2 indicates the storage at 60∘C. Determine the value of test statistic. Round your answer to two decimal places (e.g. 98.76).