MAP4C Lines of Best Fit Day # 2 Homework

  1. The table shows the age in years and the diameter in centimeters of a particular species of tree.

a) Draw a scatter plot of the data. Put age on the horizontal axis and diameter on the vertical axis. Copy the graph.
b) Describe any trends in the graph. Is there a correlation between the diameter on the vertical axis. Copy the graph.
c) Determine the equation of the line of best fit.
d) Graph the equation of the line of best fit and the scatter plot on the same screen. How well does the line fit the data? Explain.
e) Estimate the age of a tree that had a diameter of 25 cm.
f) Estimate the diameter of a 10-year-old tree.

  1. The table gives the heights and masses of 13 students.


a) Plot the data in a scatter plot. Put height on the horizontal axis and mass on the vertical axis.
b) Determine the equation of the regression line of best fit.
c) Graph the equation of the line of best fit on the same screen as the scatter plot. Does it appear to be a good fit? Explain.
d) Predict the height of a student with mass 80 kg.
e) Predict the mass of a student who is 2 m tall.

  1. The table gives data for the top ten money leaders in the Ladies Professional Golf Association (LPGA) for the 2001 golf season.

a) Draw a scatter plot of earnings versus number of events played. Copy the graph.
b) Describe any trends in the graph. Is there a correlation between a player’s earnings and the number of events she played?
c) Is it appropriate to find a line of best fit for earnings versus number of events played? Explain.

  1. The table gives the winning times in seconds for the men’s Olympic 100-m dash.


a) Enter the years in the list L1 and the times in list L2. Find the equation of the regression
line of best fit.
b) Use the equation to predict the winning time in the 100-m dash in 2008.

  1. An Obstetrician checks the measurements of various parts of a fetus using ultrasound technology. She determines whether the baby is developing at a healthy rate by comparing the baby’s measurements to a table that shows average sizes for particular stages of development. A portion of this table is reproduced here.

a) Enter the ages in list L1 and the head circumferences in list L2. Find the equation of the line of
best fit.
b) Use the equation to estimate an average measurement of head circumference for a fetus aged 30
weeks.
c) A pregnant woman has an ultrasound examination. The head circumference of the fetus is 20.6
cm. What age in weeks does the doctor predict for the fetus?

  1. To investigate the resistance in an electrical circuit, Rose measured the voltages when different currents passed through the circuit. Her data is given in the table.

a) Enter the currents in list L1 and the voltages in list L2. Draw a scatter plot of the data and
and determine the equation of the line of best fit. Copy the graph and equation.
b) Estimate the voltage when the current is 5 A.
c) Use the equation of the line of best fit to estimate the voltage when the current is 0 A. Does your
answer make sense? Explain.

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