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## Statistics and probability

### Course: Statistics and probability>Unit 5

Lesson 3: Introduction to trend lines

# Equations of trend lines: Phone data

Paige collected data on how long she spent on her phone compared to how much battery life was remaining (in hours) throughout the day. Here is the data:
Time spent on phone (hours)123, point, 546789
Battery life remaining (hours)8775, point, 553, point, 52, point, 52, point, 5
A scatterplot plots points x y axis. The y axis is labeled Battery life remaining in hours. The x axis is labeled Time spent on phone in hours. Points fall diagonally in a narrow pattern between the points points (1, 8) and (9, 2 and 1 half). All values estimated.
Now she wants a trend line to describe the relationship between how much time she spent on phone and the battery life remaining. She drew three possible trend lines:
A scatterplot plots points x y axis. The y axis is labeled Battery life remaining in hours. The x axis is labeled Time spent on phone in hours. Points fall diagonally in a narrow pattern between the points points (1, 8) and (9, 2 and 1 half). All values estimated. Line A decreases through the points (0, 9) and (8, 3). Line B decreases through the points (0, 6) and (8, 0). Line C decreases passing through the points (0, 5) and (10, 4).
problem 1
Which line fits the data graphed above?

problem 2
2) Which equation describes the best trend line above?

problem 3
Use the equation of the trend line to predict the battery life remaining after 3, point, 6 hours of phone use.
hours

problem 4
Use the trend line to predict the battery life remaining after 20 hours of phone use.
hours

problem 5
Does the prediction from problem 4 seem reasonable in the context of the problem?

problem 6
What is the best interpretation of the slope of this trend line?