C. For the test in part (i), how many degrees of freedom does the distribution of the test statistic have? D. What is the value of the observed test statistic associated with the test in part (i)? E. What is the p-value associated with the test in part (i)?
There are many different properties of wood, for example, thermal conductivity, vapor permeance and air permeability. The dry density of wood is often used as a measure of shear strength. A study was conducted to compare the strengths of oriented strand board (OSB) and plywood. Independent random samples of each type of wood were obtained and the dry density of wood (in kg/m3) was measured.
(i) Assuming that the population standard deviations of the two groups are the same, test, at the 2% level of significance, whether the dry density of OSB is different to that of plywood.
A. Use graphs (see photos) to produce the information to perform the hypothesis test in part (i).
B. Is the normality requirement satisfied for the test in part (i)? Explain
C. For the test in part (i), how many degrees of freedom does the distribution of the test statistic have?
D. What is the value of the observed test statistic associated with the test in part (i)?
E. What is the p-value associated with the test in part (i)?
F. At the 2% level of significance, does the p-value support the claim that the dry density of OSB is different to that of plywood?
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