12. Western Pygmy-Possum. The foraging behavior of the western pygmy-possum was investigated in the article "Strategies of a Small Nectarivorous Marsupial, the Western Pygmy-Possum, in Re-sponse to Seasonal Variation in Food Availability" (Journal ofMam-malogy, Vol. 96, No. 6, pp. 1525-1535) by D. Morrant and S. Petit.

The weights of adult male pygmy-possums in Australia are normally distributed with a mean of 8.5 g and a standard deviation of 0.3 g.

a. Sketch the normal curve for the pygmy-possum weights. b. Find the sampling distribution of the sample mean for samples of size 4. Draw a graph of the normal curve associated with x. c. Repeat part (b) for samples of size 9.

13. Western Pygmy-Possum. Refer to Problem 12. a. Find the percentage of all samples of four pygmy-possums that have mean weights within 0.225 g of the population mean weight of 8.5 g. b. Obtain the probability that the mean weight of four randomly selected pygmy-possums will be within 0.225 g of the population mean weight of 8.5 g. c. Interpret the probability you obtained in part (b) in terms of sampling error. d. Repeat parts (a)-(c) for samples of size 9.