Compute the population variance 2 for the following sample data, assuming the sample comprises the entire population. Round your answer o the nearest hundredth. 22 18 12 31 27 Select one: O a. 55.50 b. 74.65 O c. 53.20 O d. 44.40 O e. 93.31 Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let y be a random variable representing annual return for the Vanguard Balanced Index (60% stock and 40% bond). For the past several years, assume the following data. Compute Sy. 12 22 0 36 33 24 25 -12 -12 X: -22 7 -4 29 15 23 16 15 -4 -5 -7 Select one: a. 96 O b. 89 c. 85 d. 93 e. 92 In one of the archaeological excavation sites, the artifact density (number of prehistoric artifacts per 10 liters of sediment) was 2.0. Suppose you are going to dig up and examine 40 liters of sediment at this site. Let r = 0, 1, 2, 3,... be a random variable that represents the number of prehistoric artifacts found in your 40 liters of sediment. Find the probability that you will find 1 or more artifacts in the 40 liters of sediment. Round your answer to the nearest ten thousandth. Select one: a. 0.0137 b. 0.0013 O c. 0.0027 d. 0.0107 e. 0.0096 At Center Hospital there is some concern about the high turnover of nurses. A survey was done to determine how long (in months) nurses had been in their current positions. The responses (in months) of 20 nurses were 27 3 4 13 29 39 31 45 12 9 6 27 33 30 32 10 21 35 9 39 A box-and-whisker plot of the data is shown below. 50 45 40 35 32.5 30 27 231 20 15 10 Find the interquartile range. Select one: O a. 40.5 O b. 23.0 O c. 42.0