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MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Following is a sample of the day-by-day change, rounded to the nearest 100 points, in the Dow Jones Industrial Average during 10 successive business days around the start of a financial crisis. (Round your answers to the nearest whole number.) 400, 500, 200, 700, 100, 900, 100, 700, 80, 100 (a) Compute the mean and standard deviation of the given sample. mean , points standard deviation 455 J points (b) Fill in the blank. HINT [See Example 2(b).] Assuming that the distribution of day-by-day changes of the Dow during nancial crises is symmetric and bell shaped, then the Dow falls by more than x points 16% of the time. What is the percentage of times in the sample that the Dow actually fell by more than that amount? -~'% 12. [1/1 Points] DETAILS PREVIOUS ANSWERS WANEFMAC7 9.4.035. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The following table shows the distribution of household incomes in 2010 for a sample of 1,000 households in a country with incomes up to $100,000. Income ($1,000) 10 30 50 70 90 Households 220 280 190 160 150 Compute the expected value , and the standard deviation o of the associated random variable X. (Round your answers to the nearest $1,000.) H = $ 45000 0 = $ 27000 If we define a "lower-income" family as one whose income is more than one standard deviation below the mean and a "higher- income" family as one whose income is at least one standard deviation above the mean, what is the income gap between higher- and lower-income families in the country? (Round your answer to the nearest $1,000.) $ 54000 Need Help? Read It 13. [0.5/1 Points] DETAILS PREVIOUS ANSWERS WANEFMAC7 9.4.037. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Hispanic Employment: Male The following table shows the approximate number of males of Hispanic origin employed in the United States in a certain year, broken down by age group. Age 15-24.9 25-54.9 55-64.9 Employment (thousands) 29,000 13,000 1,100 (a) Use the rounded midpoints of the given measurement classes to compute the expected value and the standard deviation of the age X of a male Hispanic worker in the United States. (Round your answers to two decimal places.) expected value 29.00 x yrs old standard deviation 12.12 X yr "b) In what age interval does the empirical rule predict that 68 percent of all male Hispanic workers will fall? (Round youranswers to the nearest year.) 16 38