MATH 225N stat correlation Y Intercepts Week 8. All Answers Correct | Chamberlain College of Nursing

Document Content and Description Below

Question Which of the following data sets or plots could have a regression line with a negative slope? • the number of miles a ship has traveled as a function of the number of years since it wa ... s launched • ________________________________________ • the number of miles a ship has traveled each year as a function of the number of years since it was launched • ________________________________________ • the number of cats living in an abandoned lot as a function of the number of years since the building was torn down • ________________________________________ • the number of cats born each year in an abandoned lot as a function of the number of years since the building was torn down • ________________________________________ Explanation Correct : the number of miles a ship has traveled each year as a function of the number of years since it was launched the number of cats born each year in an abandoned lot as a function of the number of years since the building was torn down The slope is related to the increase or decrease of the dependent variable as a function of the independent variable. If the dependent variable can decrease, then the slope can be negative, such as with the number of cats born each year. Your : the number of miles a ship has traveled as a function of the number of years since it was launched The distance a ship has traveled can only increase, so the slope of the line can only be positive. the number of miles a ship has traveled each year as a function of the number of years since it was launched Question A plot of time versus the price of a best-selling model of television has horizontal units of years since 2000 and vertical units of dollars. The best fit line of the data are defined by the equation y=−75x+550, where x=year and y=price. What are the units of the slope? ________________________________________ Perfect. Your hard work is paying off ? ________________________________________ year dollars dollars per year years per dollar television model Explanation Correct : dollars per year The slope of the best fit line has units of dollars per year because the line represents the number of dollars the price drops each year. The price decreases as opposed to increases because the slope is negative. Question A scientific study on gerbil population growth results in the data below. x y 8 63 11 77 14 86 17 90 20 140 The least squares regression line modeling this data is given by yˆ=13.3+5.567x. What is the intercept of the regression line? Round your to one decimal place. ________________________________________ Well done! You got it right. ________________________________________ $$13.3 Explanation Correct s: • $13.3$13.3 The equation y=mx+b defines a line with a slope of m and a y-intercept of b. In this case the intercept or the constant added to x is 13.3. Question A scientific study on gerbil population growth results in the data below. x y 8 63 11 77 14 86 17 90 20 140 The least squares regression line modeling this data is given by yˆ=13.3+5.567x. What is the slope of the regression line? Round your to three decimal places. ________________________________________ Correct! You nailed it. ________________________________________ $$5.567 Explanation Correct s: • $5.567$5.567 The equation y=mx+b defines a line with a slope of m and a y-intercept of b. In this case the slope or the coefficient of x is 5.567. Question The scatter plot below shows data for the average cost of a high-end computer (y, in dollars) in the year x years since 2000. The least squares regression line is given by yˆ=−1677+314x. A coordinate plane has a horizontal x-axis labeled Year from 4 to 12 in increments of 2 and a vertical y-axis labeled Cost in dollars from 0 to 2000 in increments of 500. The following points are plotted: left-parenthesis 6 comma 250 right-parenthesis, left-parenthesis 7 comma 550 right-parenthesis, left-parenthesis 9 comma 1000 right-parenthesis, left-parenthesis 10 comma 1300 right-parenthesis, and left-parenthesis 11 comma 2000 right-parenthesis. A line rises from left to right, passing through left-parenthesis 7 comma 550 right-parenthesis and left-parenthesis 10 comma 1500 right-parenthesis. All coordinate are approximate. Interpret the slope of the least squares regression line. ________________________________________ Great work! That's correct. ________________________________________ On average, the average cost of a high-end computer is predicted to decrease by $314 each year. On average, the average cost of a high-end computer is predicted to increase by $314 each year. The average cost of a high-end computer increases by $314 each year. On average, the average cost of a high-end computer is predicted to decrease by $1677 each year. Explanation Correct : On average, the average cost of a high-end computer is predicted to increase by $314 each year. Since the slope of the line is positive 314, on average, the average cost of a high-end computer is predicted to increase by $314 each year. [Show More]

Last updated: 1 year ago

Preview 1 out of 6 pages