Malaha Dib-u-noqoshada Toosan iyo Kediska Falanqaynta Hadhaaga

Jawaabaha iyo sharraxaadaha waxay soo baxayaan markaad qaadanayso kediska.

1. Dhul-ku-habboon-ku-habboon-ku-habboon wuxuu isu-laabmaa qaab cad oo U ah. Welwelkee ayaa qaabkani kor u qaadayaa marka hore?
   • The mean relationship may need a nonlinear term
   • The residual spread may change across fitted values
   • The residual distribution may have heavy tails
   • Residuals may remain correlated across time
2. Marka qiyamka ku habbooni uu kordho, faafinta hadhaaga waxay u koraan taageere. Xaaladdee qadiimiga ah ayaa si toos ah su'aasha loo weydiinayaa?
   • Predictor measurements are exact
   • Errors have constant conditional variance
   • The conditional mean equals zero everywhere
   • Predictors are normally distributed
3. Waa maxay sababta qaladka caadiga ah ee loo qaybiyo aan loogu baahnayn oo kaliya si loo xisaabiyo isku-beegyada caadiga ah ee ugu yar?
   • OLS coefficients are calculated by minimizing squared residuals
   • Gaussian errors are required to calculate the least-squares coefficients
   • Constant variance is required for the least-squares minimizer to exist
   • Independent errors are required to compute fitted values
4. Hadhaaga baahida maalinlaha ah waxay ahaanaysaa mid togan usbuuc ka dib kororka. Maxaa la gudboon falanqeeyuhu?
   • A missing time pattern may shift the conditional mean
   • The residual variance may vary by period
   • Whether consecutive errors are dependent over time
   • A few outliers may account for the sequence
5. Barku waxa uu leeyahay saadaaliyayaal ka fog inta soo hadhay laakiin waa hadhaaga dhexdhexaad ah. Sharaxadee ayaa laga yaabaa in wali lagu dabaqi karo?
   • It has high leverage
   • It must have zero influence
   • It proves heteroscedasticity
   • It is a response outlier by definition
6. An influential observation changes the fitted slope. What is the sound first response?
   • Delete it immediately because influence proves the record is invalid
   • Inspect its source and report how the fit changes with and without it
   • Replace its response with the fitted value before checking the record
   • Keep it automatically because the complete sample is always preferable
7. Which plot is most directly used to compare residual quantiles with a normal distribution?
   • Residuals against time
   • A normal Q-Q plot
   • A fitted-versus-observed plot
   • A predictor correlation matrix
8. A residual plot looks patternless on training data. What evidence is still needed before relying on predictions?
   • Independent or later data reflecting intended use
   • A normal Q-Q plot on the same training residuals
   • A lower training squared error than a simpler model
   • A robust covariance estimate for the fitted coefficients