http://www.ck12.org Chapter 15. Concepts of Statistics
TABLE15.21:
Day # of people who know the rumor
1 2
2 8
3 29
5 161
6 372
7 378
8 391- Use logistic regression to determine an equation that models the number of people who know the rumor over
time. - Why is the logistic model appropriate in this case?
- Use your regression equation to predict the time when only one person knew the rumor. Does this make sense?
The data table below represents how the tide changes the depth of the ocean water at a beach. At a certain place in
the water, a scientist measures the depth of the water for ten consecutive hours.
TABLE15.22:
Hours Depth of Ocean Water (ft)
0 9
1 11.2
2 12.4
3 12.9
4 12.5
5 11
6 8.9
7 7
8 5.5
9 4.9
10 5.4- Choose the function family that is the best model for this situation and determine the regression equation.
- Use your regression equation to predict the depth of the water at 10 hours. What is the difference between the
actual depth from the data and the predicted depth from your equation (residual)? - Do a cubic regression on the calculator. What is the cubic regression equation? Is this a better or worse model
than the model you originally chose? - Why might statisticians do modeling with regression for their data?
You started by working with univariate data and learned how to display it graphically and summarize it numeri-
cally. You learned how to calculate mean, median, mode and variance, and when to use each. You also explored
bivariate data and used the regression capabilities of your calculator to create mathematical models for real world
phenomenon.