Imagine that you work as the quality engineer for a foam manufacturer. 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 eight samples at each storage condition were recorded. There are two storage conditions (50^oC and 60^oC) and the sample data showing the thicknesses for each storage condition is as follows. Alpha is 5% 50^oC

 

(a) Is there evidence to support the claim that mean compression (thickness) increases with the temperature at the storage condition? Alpha =5% 

(b) Find a 95% confidence interval for the difference in the mean compression for the two temperatures. (c) Is the value zero contained in the 95% confidence interval? Explain the connection with the conclusion you reached in part (a).

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50°C : 0.047, 0.060, 0.061, 0.064, 0.080, 0.090, 0.118, 0.165, 0.183 60 °C: 0.062, 0.105, 0.118, 0.137, 0.153, 0.197, 0.210, 0.250, 0.375 50°C : 0.047, 0.060, 0.061, 0.064, 0.080, 0.090, 0.118, 0.165, 0.183 60 °C: 0.062, 0.105, 0.118, 0.137, 0.153, 0.197, 0.210, 0.250, 0.375