题目1667 · 统计
A sample is {1,4}. Under the nonparametric bootstrap with resample size 2, compute the bootstrap expectation of the sample maximum and the resulting bootstrap bias estimate for the original maximum statistic.
打开 →题目1668 · 统计
A sample of size n has empirical success rate p_hat. Under the nonparametric bootstrap, what is the variance of the resampled sample mean conditional on the observed data?
打开 →题目1666 · 统计
A sample is {a,b}. In the nonparametric bootstrap, a resample of size 2 is drawn with replacement. Derive the variance of the bootstrap sample mean.
打开 →题目1670 · 统计
If a statistic is the sample mean and you use an m-out-of-n nonparametric bootstrap instead of an n-out-of-n bootstrap, how does the conditional variance of the resampled mean scale with m?
打开 →题目1672 · 统计
Why can a residual bootstrap be invalid for regression under heteroskedasticity while a pairs bootstrap remains defensible?
打开 →题目1679 · 统计
When can a parametric bootstrap be more informative than a nonparametric bootstrap?
打开 →题目1669 · 统计
A sample is {0,0,10}. Under the nonparametric bootstrap with resample size 3, what values can the bootstrap median take, and what condition determines which one occurs?
打开 →题目1678 · 统计
Why is the point of a block bootstrap not merely to resample larger chunks, but to preserve local serial dependence?
打开 →题目5163 · 金融与交易
Why does curve bootstrapping solve short maturities first and then move outward one maturity at a time?
打开 →题目1680 · 统计
Why can a bootstrap study itself become overfit if you repeatedly choose tuning knobs by looking at the same resampled diagnostics?
打开 →题目1675 · 统计
What conceptual idea makes the basic bootstrap interval differ from the percentile interval?
打开 →题目1676 · 统计
Why is the nonparametric bootstrap often too optimistic about tail risk when the observed sample contains no truly extreme events?
打开 →题目1671 · 统计
An estimator is constrained to be nonnegative and lands exactly at 0 on the observed sample. Why can the naive nonparametric bootstrap badly misrepresent uncertainty near that boundary?
打开 →题目5075 · 机器学习
A tabular Q-learning step starts from old Q=0, uses learning rate alpha=0.5, reward 0.1, and discount gamma=0.99. After the update the Q-value becomes 3. What max_a' Q(s',a') must the learner have used?
打开 →题目5071 · 机器学习
A tabular Q-learning step starts from old Q=0.2, uses learning rate alpha=1, reward 0.5, and discount gamma=0.9. After the update the Q-value becomes 2.9. What max_a' Q(s',a') must the learner have used?
打开 →题目5072 · 机器学习
A tabular Q-learning step starts from old Q=1.1, uses learning rate alpha=0.5, reward 0.2, and discount gamma=0.8. After the update the Q-value becomes 1.6. What max_a' Q(s',a') must the learner have used?
打开 →题目5073 · 机器学习
A tabular Q-learning step starts from old Q=-0.4, uses learning rate alpha=0.25, reward 1, and discount gamma=0.95. After the update the Q-value becomes 1.2. What max_a' Q(s',a') must the learner have used?
打开 →题目5074 · 机器学习
A tabular Q-learning step starts from old Q=0.7, uses learning rate alpha=0.4, reward 0.3, and discount gamma=0.9. After the update the Q-value becomes 2. What max_a' Q(s',a') must the learner have used?
打开 →题目1673 · 统计
Why should a practitioner resample accounts, users, or securities rather than individual rows when observations inside each group share latent shocks?
打开 →题目5086 · 机器学习
Why can bootstrapping help value estimates even before an episode terminates?
打开 →题目5089 · 机器学习
Why can off-policy learning become fragile when function approximation, bootstrapping, and distribution shift all interact?
打开 →题目1677 · 统计
Why can studentizing a bootstrap statistic improve interval accuracy in skewed or scale-varying problems?
打开 →题目1674 · 统计
Why can a percentile bootstrap interval end up noticeably off-center relative to the original estimate when the statistic is skewed?
打开 →模块2.2.1 · 数学与统计能力 · 统计推断
MLE · 假设检验 · 置信区间 · Bootstrap
打开 →课程参数估计与假设检验 · 统计推断
上海某私募的量化研究员把上一课跑出来的两个候选估计量并排放着:一个是无偏的样本方差 公式(分母 公式),另一个是极大似然估计(maximum likelihood estimation, MLE)的方差版 公式(分母 公式)。直觉告诉他「无偏」听起来更值得信赖,但当真到了要在波动率模型里塞一个数,他需要的是一把明确可比较的「好坏」尺子——能告诉他在 公式 的...
打开 →课程债券基础 · 固定收益
周三晚上,某 私募 宏观对冲基金的策略会议上,研究员摔出一张图:「2Y CGB 收益率比 10Y 还高了 8bp,曲线倒挂了。要不要做平 2 10 利差?」要回答这个问题,你得先把「2Y vs 10Y」这两个点背后的曲线讲清楚——它是怎么画出来的、上面的点对应的是哪种「率」、不同形状对应什么宏观状态。本课把这条曲线建起来。 曲线是什么 收益率曲线(yield...
打开 →课程SciPy 与统计工具 · Python 数据与量化分析
周五下午两点半,浦东陆家嘴一家中型私募的风控会上,PM 把昨晚跑出来的 tear sheet 推过来:「食品饮料这只 600519.SH 的 63 日滚动 夏普比率 (Sharpe ratio)样本期均值是 0.86,银行那两只 000001.SZ 和 600036.SH 是 0.42。0.44 的差,可信吗?」你脑子里第一反应是 3.2.2 L5 那...
打开 →题目5088 · 机器学习
Why does increasing the discount factor often make value estimates more sensitive to long-run model misspecification?
打开 →题目5151 · 金融与交易
A 1.5-year bond with face 100 has annual coupon rate 4.0%, paid semiannually, and trades at 100.911. The discount factors are D(0.5)=0.985 and D(1.0)=0.968. Assume the annual-compounded forward rate from 1.0 years to 1.5 years is flat over that stub. What forward rate is implied?
打开 →题目5090 · 机器学习
Why should a quant be careful when mapping a toy MDP intuition directly into live trading?
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