3.9 A community in the San Francisco Bay area consists of approximately 50,000 persons, of whom approximately 40% are Caucasians, 25% are African American, 20% are Hispanic, and 15% are Asian. It is desired to estimate in this community the proportion of persons who are not covered by some form of health insurance. One would like to be 95% certain that this estimate is within 15% of the true proportion, which is believed to lie somewhere be- tween 10% and 20% of the total population. Assuming simple random sam- pling, how large a sample is needed?

2. This table shows the mean and median total cash income for married-couple households (including wages, public assistance, interest/dividends, Social Security, pensions, etc.), by race and Hispanic origin. a apaa Median Household Mean Household Income ($) Income ($) Asian 110,453 78,010 66,893 110,138 145,948 Black 97,667 Hispanic White, non-Hispanic 88,450 129,142 a. Pick one group and interpret the median and the mean. b. For each group, how do the mean and the median compare? Explain why you think this must be the case.

6. A social worker looks at data in her state regarding the relationship between being in foster care and having a criminal record by the age of 25. "Aging out' refers to when a youth turns 18 years old and is expected to move out of foster care and start their lives on their own. Fictional data fro 1350 youths is shown below. Answer the following questions in the space below, labeling each response a, b, or c. What percentage of youths overall were adopted before aging out, and had a criminal record?                           What percentage of youths were in foster care until they were aged out?                           True or False: If foster care status and having a crime record were independent of each other, and 55% overall had no crime record, you would expect 55% of those who aged out in foster care to have no crime record.       No crime record Crime record Total Foster care until ‘aged out’ 445 450 895 Adopted before aging out 300 155…

To boost holiday sales, Ginsberg jewelry store is advertising the following promotion: “If more than five inches of snow fall in the first three days of the year (January 1 through January 3), all purchases made between Thanksgiving and Christmas are free!” Based on historical sales records as well as experience with past promotions, the store manager believes that the total holiday sales between Thanksgiving and Christmas could range anywhere between $200,000 and $400,000 but is unsure of anything more specific. Ginsberg has collected data on snowfall from December 16 to January 18 for the past several winters in the file Ginsberg. Construct a simulation model to assess potential refund amounts so that Ginsberg can evaluate the option of purchasing an insurance policy to cover potential losses. What is the probability that Ginsberg will have to refund sales? What is the average refund? Why is this a poor measure to use to assess risk? In the cases when snowfall exceeds 5…

A hospital wants to estimate the percentage of admitted patients who receive Medicare benefits. If we want to estimate that percentage based on examination of randomly selected patient payment records, how many patient records must be examined in order to be 90% confident that we are within four percentage points of the population percentage?

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An Associated Press story in Easton, Maryland’s The Star Democrat on June 3, 2010 reported thatAll told, scam artists are believed to have stolen about $47 billion from Medicare in the 2009 fiscal year, nearly triple the toll a year earlier. Medicare spokesman Peter Ashkanaz said that…charges have been filed against 103 defendants in cases involving more than $100 million in Medicare fraud.(a) What percentage of the Medicare fraud has been targeted by filed charges?(b) What is the average claim in each fraud charge?(c) How many of these average size claims would need to be filed to recover the entire $47 billion?