Figure 4
Bootstrap for weekends. (a) shows the results of the bootstrap for couples of Large cities during the weekends. The point and the bars represent the mean and the standard deviation obtained for each couple using the jackknife sampling method. The shaded area represents the 95% confidence interval obtained using the bootstrap method described in Materials and methods and the line represents the bootstrapped Weighted Least-Square Regression (WLS) fit. (b) as (a) but for the Medium cities. (c) as (a) but for Small cities. (d) summarizes the estimates of the bootstrap regression previously obtained in figures (a)–(c). Note that error bars and confidence intervals are larger, due to less data availability for weekends (our dataset consists of 6 weekend days and 18 weekdays)