Step 1. Decade intervals of the mean monthly return (95 percent t intervals), percent:
   1926 to 1929   n=  42  mean +1.47  interval [-0.31, +3.25]  contains zero
   1930s          n= 120  mean +0.50  interval [-1.38, +2.38]  contains zero
   1940s          n= 120  mean +0.86  interval [+0.05, +1.67]
   1950s          n= 120  mean +1.46  interval [+0.88, +2.05]
   1960s          n= 120  mean +0.73  interval [+0.07, +1.39]
   1970s          n= 120  mean +0.61  interval [-0.28, +1.50]  contains zero
   1980s          n= 120  mean +1.43  interval [+0.55, +2.30]
   1990s          n= 120  mean +1.47  interval [+0.75, +2.19]
   2000s          n= 120  mean +0.08  interval [-0.78, +0.95]  contains zero
   2010s          n= 120  mean +1.14  interval [+0.46, +1.81]
   2020 to 2025   n=  72  mean +1.29  interval [+0.08, +2.50]
   Full series    n=1194  mean +0.96  interval [+0.66, +1.26]
   Era intervals containing zero: 4 of 11

Step 2. Win rate 8 of 12 = 0.667; Wald margin of error 0.267, interval [0.400, 0.933]; Wilson interval [0.391, 0.862]

Step 3. Hand run: twenty-five resamples of the first ten SPY months of 2023
   First resample indices: 10, 5, 3, 8, 3, 2, 2, 8, 8, 9 
   First resample mean: -0.894 percent; standard deviation of the twenty-five resample means: 1.022 percent; resample means below zero: 5

Step 4. Bootstraps at seed 20261020 (this step takes a few minutes):
   Simple bootstrap, mean: interval [0.66, 1.25] percent
   Block bootstrap (L = 12), mean: interval [0.63, 1.27] percent; width ratio to the simple interval 1.09
   Simple bootstrap, median: interval [1.09, 1.65] percent
   Block bootstrap (L = 12), maximum drawdown: interval [-85.9, -44.6] percent (observed -83.7)
   Block bootstrap (L = 24), maximum drawdown: interval [-90.1, -46.1] percent (observed -83.7)
   Block bootstrap (L = 36), maximum drawdown: interval [-92.3, -48.3] percent (observed -83.7)

Part B, R lane solution: CAGR of the 2010s, observed 13.60 percent a year
   Simple bootstrap interval: [4.89, 22.91] percent a year
   Block bootstrap interval (L = 12): [7.60, 19.40] percent a year

Chapter 6 lab complete.
