Variance measures spread around the mean, so the squared distance keeps positive and negative deviations from cancelling.
方差衡量数据在均值周围的离散程度；将距离平方，可以避免正负偏差相互抵消。
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STAT2011Week 5 · Random variables
TranscriptOriginal · EnglishTranslation · Simplified Chinese
Original · EnglishIndependence is stronger than zero covariance; keep those two ideas separate when you justify a step.
Translation · Simplified Chinese独立比零协方差更强，推导时要把这两个概念分清楚。
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00:32STAT2011 · Week 5 · Random variables
Original · English
Independence is stronger than zero covariance; keep those two ideas separate when you justify a step.
Translation · Simplified Chinese
独立比零协方差更强，推导时要把这两个概念分清楚。
02
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From the transcript
A distinction worth keeping.
Professor Vale stressed that independence is stronger than zero covariance and that the distinction must be stated, not assumed.
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A distinction worth keeping
STAT2011Week 5 · Random variables
What you heard
00:32
Independence is stronger than zero covariance; keep those two ideas separate when you justify a step.独立比零协方差更强，推导时要把这两个概念分清楚。
What you kept
Professor Vale stressed that independence is stronger than zero covariance and that the distinction must be stated, not assumed.
What you remember
Is zero covariance enough to establish independence?
Show answerHide answer
No. Independence is stronger than zero covariance.
Illustrative review content
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Independence & covariance
From the transcript · User-verified excerpt
Professor Vale stressed that independence is stronger than zero covariance and that the distinction must be stated, not assumed.
Independence is stronger than zero covariance; keep those two ideas separate when you justify a step.Return to the source 00:32Illustrated product experience · Sample class content
Decks
STAT2011
Independence & covariance
Prompt
Is zero covariance enough to establish independence?
Show answerHide answer
No. Independence is stronger than zero covariance.
Illustrative review content
Illustrated mobile review · Same concept, sample card
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