A survey collects demographic, socioeconomic, dietary, and health-related information on an annual basis. Here is a sample of20 observationson HDL cholesterol level (mg/dl) obtained from the survey (HDL is "good" cholesterol; the higher its value, the lower the risk for heart disease).

Data:

34. 48. 51. 53. 64. 50. 50.

46. 85. 35. 45. 32. 38. 44

40. 64. 96. 36. 31 47

a. Calculate a point estimate (in mg/dl) of the population mean HDL cholesterol level.

b. Making no assumptions about the shape of the population distribution, calculate a point estimate (in mg/dl) of the value that separates the largest 50% of HDL levels from the smallest 50%.

c. Calculate a point estimate (in mg/dl) of the population standard deviation. (Round your answer to three decimal places.)

d. An HDL level of at least 60 is considered desirable as it corresponds to a significantly lower risk of heart disease. Making no assumptions about the shape of the population distribution, estimate the proportionpof the population having an HDL level of at least 60.

p=?