Estimates of the mean interearthquake times
The graphical EDA in the last exercise shows an obvious change in earthquake frequency around 2010. To compare, compute the mean time between earthquakes of magnitude 3 and larger from 1980 through 2009 and also from 2010 through mid-2017. Also include 95% confidence intervals of the mean. The variables dt_pre and dt_post respectively contain the time gap between all earthquakes of magnitude at least 3 from pre-2010 and post-2010 in units of days.
This exercise is part of the course
Case Studies in Statistical Thinking
Exercise instructions
- Compute the mean interearthquake time for pre- (
dt_pre) and post-2010 (dt_post). - Draw 10,000 bootstrap replicates of the mean for the pre- and post-2010 datasets.
- Use
np.percentile()to compute the 95% confidence interval of the mean for both datasets. - Hit 'Submit Answer' to print the results to the screen.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Compute mean interearthquake time
mean_dt_pre = ____
mean_dt_post = ____
# Draw 10,000 bootstrap replicates of the mean
bs_reps_pre = ____
bs_reps_post = ____
# Compute the confidence interval
conf_int_pre = ____
conf_int_post = ____
# Print the results
print("""1980 through 2009
mean time gap: {0:.2f} days
95% conf int: [{1:.2f}, {2:.2f}] days""".format(mean_dt_pre, *conf_int_pre))
print("""
2010 through mid-2017
mean time gap: {0:.2f} days
95% conf int: [{1:.2f}, {2:.2f}] days""".format(mean_dt_post, *conf_int_post))