AP Statistics US SA practice: Transformations to Achieve Linearity Questions 7 through 9 involve the following data set. noMe ur work a Increase in Life Expectancy in the United States . this during the 20th Century Expected Expected and Year Life Span Year Life Span 1920 54.1 1975 72.6 1930 59.7 1980 73.7 =+/or -1 p to you 1940 62.9 1985 74.7 tion + ake log of both 1950 68.2 1990 75.4 1960 69.7 1995 75.8 70 - 90 1970 70.8 be can say there Source: National Center for Health Statistics, published 1 actual Medicare in the 1998 World Almanac Since the maynitate of the 7. Make a scatterplot of the untransformed data and tell which kind of relationship the points seem to follow. Also name the best type of close transformation needed to "straighten" the plot. (3 points) so the model Note: Part of the transformation should Involve subtracting 1900 from the year so Put for the data you're working with more manageable numbers. scribe called alues zebraically convert Now try some transformations to get the data as close to linear as possible. ay to (Use your calculator to transform the data, and try scatterplots of the different transformations). Then find the regression line, r, and r2. (4 points) o the linearly transformation worked the best and back it up by showing: with the least-squares regression equation and