Action! Investigate Line of Best Fit Materials Darla's parents kept track of her height on her birthday every year . transparent ruler from ages two through eight. The graph shows the measurements as a time series. 120 100 Literacy Link Height (cm) A time series is a set of two-variable data 60 in which a quantity is measured against 40 time 4 6 8 10 Age (years) Literacy Link An independent 1. Identify the independent and dependent variables. How do you know? variable is a not affected by another 2. Does there appear to be a relationship between Darla's height and her variable. A dependent variable is affected by age? If so, describe it. another variable3. a) Sketch the graph and draw a line of best fit. line of best fit b) Does it make sense to draw a solid or a dashed line in this case? . a straight line that Explain why. represents a trend in the scatter plot as 4. Extend the line to answer the following questions. long as the pattern is more or less linear a) How tall will Darla be at age 10? should pass through b) Estimate Darla's height when she was a newborn. as many points as possible, with about 5. Reflect half the points above a) How accurate do you think these estimates are? Explain. and half below the line b) Will this trend continue forever? If not, when will this linear - a solid line model no longer be useful? Explain your reasoning. represents continuous data Darla's parents also kept track of the that are constantly number of baby teeth she still had, except changing for one year when they forgot. The data. 20 . a dashed line collected on her birthdays, are shown. represents discrete 181 data that change only 6. Identify the independent and in steps 16 dependent variables. Literacy Link Baby Teeth' 7. Does there appear to be a correlation 12 Interpolation and between the number of baby extrapolation are teeth Darla had and her age? If so, 10 important tools for two- describe it. variable data analysis. 8 To interpolate, read a 8. a) Sketch the graph and draw a line of inear model between given data points. best fit. To extrapolate, read Age (years) b) Does it make sense to draw a solid beyond given data points. or a dashed line in this case? Explain why. c) Use the line to estimate how many baby teeth Darla had on her sixth birthday.9. Reflect a) How accurate do you think this estimate is? Explain. b) Will this trend continue forever? Why or why not? 10. Reflect Compare the two lines of best fit that you drew in this investigation. a) Was one easier to draw than the other? b) Was one a better model for the data than the other? Justify your answers