A variable of two populations has a mean of 40 and a standard deviation of 12 for one of the populations and a mean of 40 and a standard deviation of 6 for the other population. a. For independent samples of sizes 9 and 4, respectively, find the mean and standard deviation of x1 - x2.b. Must the variable under consideration be normally distributed on each of the two populations for you to answer part (a)? Explain your answer.c. Can you conclude that the variable x1 - x2 is normally distributed? Explain your answer.

Question

A variable of two populations has a mean of 40 and a standard deviation of 12 for one of the populations and a mean of 40 and a standard deviation of 6 for the other population.

a. For independent samples of sizes 9 and 4, respectively, find the mean and standard deviation of x1 - x2.
b. Must the variable under consideration be normally distributed on each of the two populations for you to answer part (a)? Explain your answer.
c. Can you conclude that the variable x1 - x2 is normally distributed? Explain your answer.

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