# Question: Eight randomly selected batches of a chemical were tested for

Eight randomly selected batches of a chemical were tested for impurity concentration. The percentage impurity levels found in this sample were as follows:

3.2 4.3 2.1 2.8 3.2 3.6 4.0 3.8

a. Find the most efficient estimates of the population mean and variance.

b. Estimate the proportion of batches with impurity levels greater than 3.75%.

3.2 4.3 2.1 2.8 3.2 3.6 4.0 3.8

a. Find the most efficient estimates of the population mean and variance.

b. Estimate the proportion of batches with impurity levels greater than 3.75%.

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