he idea of a large, stable middle class (defined as those with annual household incomes in 2010 between $42,000 and $126,000 for a family of three), is central to America's sense of itself. But the U.S. middle class shrank steadily from 61% of all adults in 1971  (t = 0)  to 51% in 2011  (t = 4),  where t is measured in decades. Research has shown that this decline was approximately linear.† (a) Find a linear function f(t) giving the percentage of middle-income adults in decade t, where  t = 0  corresponds to 1971. f(t) =    (b) If this trend continues, what will the percentage of middle-income adults be in 2021?  %

II.

According to a high-profile realtor, houses in the sleepy town of Sun Beach have shown higher appreciation over the past three years than have houses in the bustling town of North Arden. To test the realtor's claim, an economist has found twelve recently sold homes in Sun Beach and twelve recently sold homes in North Arden that were owned for exactly three years. The following table gives the appreciation (expressed as a percentage increase) for each of the twenty- four houses. Appreciation rates in percent Sun Beach 12.5, 12.2, 10.4, 12.9, 6.5, 15.0, 10.1, 10.6, 12.1, 10.8, 10.4, 9.1 North Arden 9.2, 10.7, 9.7, 7.8, 9.7, 12.1, 9.4, 6.1, 7.8, 9.3, 4.6, 11.0 Send data to calculator v Assume that the two populations of appreciation rates are normally distributed and that the population variances are equal. Can we conclude, at the 0.05 level of significance, that houses in Sun Beach have higher appreciation over the past three years than houses in North Arden? Perform a one-tailed test.…

The following are historical demand data: ACTUAL YEAR 2011 SEASON DEMAND Spring 201 Summer 142 Fall 380 Winter 578 2012 Spring 469 Summer 273 Fall Winter 683 963 Use regression analysis on deseasonalized demand to forecast demand in summer 2013. (Do not round intermediate calculations. Round your answer to the nearest whole number.) Forecast for summer 2013

An entrepreneur who owns and operates two businesses (A and B) would like to analyze their profitability. They would like your help in the analysis. They give you the annual net profit (in thousands of $) for each business from 2008-2020. Table 1: Annual Net Profits for Businesses A and B Business Year Profit Business Year Profit 2008 -50 2008 -10 2009 57 2009 30 2010 71 2010 27 2011 64 2011 22 2012 60 2012 21 2013 50 2013 20 A 2014 41 2014 24 2015 59 2015 24 2016 71 2016 32 2017 71 2017 36 2018 74 2018 37 019 81 20 40 2020 97 2020 49 a. Suppose you want to graph the distribution of profits. Explain why using only one stem- plot might not be optimal for the analysis. b. Describe the correct stemplot to use. Generate this stemplot. Explain your steps. What can you say about the distribution from this stemplot? c. When are stemplots useful? And why is that? d. Suppose that instead of having 26 observations you have 200 observations. What graph should you generate? e. What other type of…

Use regression analysis on deseasonalized demand to forecast demand in summer 2013. Forecast for summer 2023 ______