scipy.stats 分布对象与描述性统计
周一上午十点,你坐在一家中型私募的研究台。3.2.2 收尾那张 tear sheet 昨晚跑完了,落到磁盘的中间产物里有一行 returns = (closes['510300.SH'].pct change().dropna()).to numpy() ——一根长度 252 的 np.ndarray ,是沪深300 ETF(510300.SH)在 2024...
打开 →GLOBAL SEARCH
搜索在服务端完成,题目解析与答案不会进入搜索结果。登录后可搜索自己的收藏题单。
找到 30 个结果
中文题目周一上午十点,你坐在一家中型私募的研究台。3.2.2 收尾那张 tear sheet 昨晚跑完了,落到磁盘的中间产物里有一行 returns = (closes['510300.SH'].pct change().dropna()).to numpy() ——一根长度 252 的 np.ndarray ,是沪深300 ETF(510300.SH)在 2024...
打开 →python · scipy · stats · distributions · fit · var · descriptive-statistics · hypothesis-testing
打开 →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 →周三午后,浦东陆家嘴一家中型私募的研究台上,PM 把一张 252 天的样本期跑出来推过来:「 600519.SH 对沪深300 ETF( 510300.SH )的 beta 我刚才用 np.linalg.lstsq 解出来是 0.91——但 0.91 离 1 到底有多远?是抽样噪音里飘出来的一格,还是这只票就比沪深300 系统性低 beta?」3.2.1 L...
打开 →周一上午十点,浦东一家中型私募的研究台。PM 把 3.2.2 L5 那张已经稳定跑通的 tear sheet 推过来,篮子是 、252 个交易日的 NumPy 收益矩阵 returns ,形状 公式。「我现在不要单只票的 alpha 也不要 Sharpe——给我四个数:第一,这只 3 票篮子的 最小方差 长仓权重;第二,顶端主成分占多少方差,看篮子风...
打开 →Two backtests differ only slightly: one reports p = 0.049 and the other p = 0.051. Why is it bad practice to call one ‘real’ and the other ‘not real’ purely because one is below 0.05?
打开 →A PM sees a frequentist 95% confidence interval for next-month strategy edge of [-0.1, 0.4] and asks, "So what is the probability the true edge is positive for this launch decision?" Why can't the interval answer that question by itself, and what Bayesian quantity would answer it
打开 →Someone proposes using yesterday's order-flow imbalance as an instrument for today's imbalance in a return-impact regression. Why is this not automatically a valid instrument in financial data?
打开 →Let $X\sim \mathrm{Binomial}(10,p)$ and consider the estimator $$\delta = \frac{X+1}{12}$$ for $p$. At the parameter value $p=0.2$, compute the bias, variance, and MSE of $\delta$, and compare its MSE with the usual sample proportion $\hat p = X/10$.
打开 →Two candidate rollouts have the same reduced-form impact on PnL: $$E[Y\mid Z=1]-E[Y\mid Z=0]=0.02.$$ For rollout A, the first stage is $0.20$; for rollout B, the first stage is $0.01$. Which rollout creates the weaker IV design, and why?
打开 →A latent profitable regime has prior probability $\frac{2}{5}$. Independent signals arrive sequentially; each `H` doubles the odds of the regime and each `T` halves them. After the signal string `HHT`, should you act if the required posterior threshold is $\frac{3}{5}$? Also repo
打开 →Suppose Xbar ~ N(theta, 0.16). A desk uses delta = 0.6Xbar + 0.8. For what values of theta does delta have lower MSE than Xbar?
打开 →A desk has 12 sectors, each containing 5 genuinely null variants. In each sector it keeps only the smallest p-value, and it flags the sector if that winning p-value is below 1%. Assuming independence, what is the probability at least one sector is falsely flagged?
打开 →A coin is flipped 20 times and lands heads 14 times. Use the normal approximation to test fairness at the 5% two-sided level.
打开 →For the AR(1) model X_t = phi X_(t-1) + e_t with phi = 0.6 and Var(e_t) = 1, what is the h = 3 step forecast error variance?
打开 →For the AR(1) model X_t = phi X_(t-1) + e_t with phi = 0.5 and Var(e_t) = 2.25, what is the h = 4 step forecast error variance?
打开 →A signal follows X_t = 0 + 0.6 X_(t-1) + e_t with Var(e_t) = 2 and current value X_t = 10. What is the h = 3 step forecast E[X_(t+3) | X_t]?
打开 →A signal follows X_t = 4 + 0.7 X_(t-1) + e_t with Var(e_t) = 1.5 and current value X_t = 8. What is the h = 2 step forecast E[X_(t+2) | X_t]?
打开 →A signal follows X_t = -1 + 0.8 X_(t-1) + e_t with Var(e_t) = 1 and current value X_t = 3. What is the h = 4 step forecast E[X_(t+4) | X_t]?
打开 →A GARCH(1,1) reduces to ARCH(1) when $\beta=0$: $h_t=\omega+\alpha r_{t-1}^2$. With $\omega=0.7$ and $\alpha=0.3$, compute the unconditional variance $\bar h$ as a decimal.
打开 →You observe the diagnostic statement: ACF tails off geometrically, PACF cuts after lag 1. What is the correct modeling conclusion?
打开 →You observe the diagnostic statement: ACF cuts after lag 1, PACF tails off. What is the correct modeling conclusion?
打开 →You observe the diagnostic statement: Both ACF and PACF tail off. What is the correct modeling conclusion?
打开 →You observe the diagnostic statement: AIC prefers ARMA(2,1) but BIC prefers ARMA(1,1). What is the correct modeling conclusion?
打开 →You observe the diagnostic statement: (1-0.5L) X_t = (1-0.5L) e_t. What is the correct modeling conclusion?
打开 →A live manager panel shows 27 low-leverage funds and 18 high-leverage funds. Survival rates for those groups were 90% and 60%, respectively. Suppose low-leverage funds average 1.2x gross leverage and high-leverage funds average 2.4x gross leverage. What was the average gross lev
打开 →A regression uses n = 25 observations and three estimated parameters including the intercept. What are (i) the average leverage and (ii) the average diagonal entry of the residual-maker matrix I - H?
打开 →Again the structural model is $Y=2X+u$ with $E[u\mid X]=0$, but now you observe two noisy proxies: $$W_1=X+\eta_1, \qquad W_2=X+\eta_2,$$ where $\eta_1,\eta_2$ are independent of each other and of $X,u$. Suppose $\operatorname{Var}(X)=4$ and each noise term has variance 1. If yo
打开 →A desk regresses slippage Y on inventory pressure X. Without an urgency control, the OLS slope on X is 0.90. After adding a perfect measure of urgency U, the slope falls to 0.60. Suppose the structural model is Y = beta X + 0.5 U + noise and Var(X)=1. What is Cov(X,U)?
打开 →A PM deck says: ‘The event-study p-value is 0.03, so there is a 97% probability the signal is real.’ What is the statistical mistake?
打开 →