{"id":31486,"date":"2023-12-07T10:40:50","date_gmt":"2023-12-07T10:40:50","guid":{"rendered":"https:\/\/masterskills.org\/blog\/do-lech-chuan-standard-deviation-la-gi-cong-thuc-tinh-do-lech-chuan.html"},"modified":"2023-12-23T08:17:42","modified_gmt":"2023-12-23T01:17:42","slug":"do-lech-chuan-standard-deviation-la-gi-cong-thuc-tinh-do-lech-chuan","status":"publish","type":"post","link":"https:\/\/masterskills.org\/blog\/do-lech-chuan-standard-deviation-la-gi-cong-thuc-tinh-do-lech-chuan.html","title":{"rendered":"\u0110\u1ed9 l\u1ec7ch chu\u1ea9n (Standard Deviation) l\u00e0 g\u00ec? C\u00f4ng th\u01b0\u0301c t\u00ednh \u0111\u1ed9 l\u1ec7ch chu\u1ea9n"},"content":{"rendered":"
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Hi\u0300nh minh ho\u0323a. Ngu\u00f4\u0300n: Wikihow.com<\/i><\/p>\n<\/div>\n<\/div>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/font><\/b><\/h2>\n

Kha\u0301i ni\u00ea\u0323m<\/b><\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> trong ti\u00ea\u0301ng Anh la\u0300 Standard Deviation<\/b>.<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> l\u00e0 m\u1ed9t ph\u00e9p \u0111o l\u01b0\u01a1\u0300ng trong th\u1ed1ng k\u00ea va\u0300 trong t\u00e0i ch\u00ednh \u0111\u01b0\u1ee3c \u00e1p d\u1ee5ng cho t\u1ec9 l\u1ec7 ho\u00e0n v\u1ed1n h\u00e0ng n\u0103m c\u1ee7a m\u1ed9t kho\u1ea3n \u0111\u1ea7u t\u01b0, \u0111\u00ea\u0309 l\u00e0m s\u00e1ng t\u1ecf nh\u01b0\u0303ng s\u1ef1 bi\u1ebfn \u0111\u1ed9ng trong l\u1ecbch s\u1eed kho\u1ea3n \u0111\u1ea7u t\u01b0 \u0111\u00f3.\u00a0<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n c\u1ee7a m\u00f4\u0323t c\u00f4\u0309 phi\u00ea\u0301u c\u00e0ng l\u1edbn, hay ph\u01b0\u01a1ng sai gi\u1eefa gi\u00e1 c\u00f4\u0309 phi\u00ea\u0301u v\u00e0 gi\u00e1 tr\u1ecb trung b\u00ecnh ca\u0300ng l\u01a1\u0301n, cho th\u1ea5y ph\u1ea1m vi gi\u00e1 giao \u0111\u00f4\u0323ng c\u00e0ng r\u00f4\u0323ng. V\u00ed d\u1ee5, m\u1ed9t c\u1ed5 phi\u1ebfu b\u00e2\u0301t \u00f4\u0309n c\u00f3 \u0111\u1ed9 l\u1ec7ch chu\u1ea9n cao, trong khi \u0111\u1ed9 l\u1ec7ch chu\u00e2\u0309n c\u1ee7a m\u1ed9t c\u1ed5 phi\u1ebfu blue-chip \u1ed5n \u0111\u1ecbnh th\u01b0\u1eddng kh\u00e1 th\u1ea5p.<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n \u0111\u01b0\u1ee3c t\u00ednh l\u00e0 c\u0103n b\u1eadc hai c\u1ee7a ph\u01b0\u01a1ng sai,\u00a0<\/b>\u0111\u01b0\u01a1\u0323c ti\u0301nh b\u0103\u0300ng ca\u0301ch x\u00e1c \u0111\u1ecbnh s\u1ef1 ch\u00eanh l\u00ea\u0323ch gi\u1eefa m\u1ed7i \u0111i\u1ec3m d\u1eef li\u1ec7u so v\u1edbi gi\u00e1 tr\u1ecb trung b\u00ecnh. N\u1ebfu m\u00f4\u0323t \u0111i\u1ec3m d\u1eef li\u1ec7u n\u1eb1m xa gi\u00e1 tr\u1ecb trung b\u00ecnh, \u0111i\u00ea\u0309m \u0111o\u0301 c\u00f3 \u0111\u1ed9 l\u1ec7ch cao trong t\u1eadp d\u1eef li\u1ec7u, d\u1eef li\u1ec7u c\u00e0ng co\u0301 \u0111\u00f4\u0323 da\u0300n tr\u1ea3i r\u1ed9ng th\u00ec \u0111\u1ed9 l\u1ec7ch chu\u1ea9n c\u00e0ng cao.<\/p>\n

C\u00f4ng th\u01b0\u0301c t\u00ednh \u0111\u1ed9 l\u1ec7ch chu\u1ea9n<\/font><\/h3>\n
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Hi\u0300nh minh ho\u0323a. Ngu\u00f4\u0300n: Wix.com<\/i><\/p>\n<\/div>\n<\/div>\n

Trong \u0111o\u0301:<\/p>\n

xi<\/sub><\/b> la\u0300 gia\u0301 tri\u0323 cu\u0309a \u0111i\u00ea\u0309m i trong t\u00e2\u0323p d\u01b0\u0303 li\u00ea\u0323u<\/p>\n

x\u0304<\/b> la\u0300 gia\u0301 tri\u0323 c\u1ee7a t\u1eadp d\u1eef li\u1ec7u<\/p>\n

n<\/b> la\u0300 t\u00f4\u0309ng s\u00f4\u0301 quan sa\u0301t trong t\u00e2\u0323p d\u01b0\u0303 li\u00ea\u0323u<\/p>\n

Gi\u00e1 tr\u1ecb x trung b\u00ecnh \u0111\u01b0\u1ee3c t\u00ednh b\u1eb1ng c\u00e1ch t\u00f4\u0309ng t\u1ea5t c\u1ea3 c\u00e1c quan sa\u0301t v\u00e0 chia cho s\u1ed1 quan sa\u0301t.<\/p>\n

Ph\u01b0\u01a1ng sai cho m\u1ed7i \u0111i\u1ec3m d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c t\u00ednh b\u1eb1ng c\u00e1ch tr\u1eeb gi\u00e1 tr\u1ecb c\u1ee7a quan sa\u0301t v\u01a1\u0301i gia\u0301 tr\u1ecb trung b\u00ecnh. K\u1ebft qu\u1ea3 sau \u0111\u00f3 \u0111\u01b0\u1ee3c b\u00ecnh ph\u01b0\u01a1ng v\u00e0 \u0111\u01b0\u1ee3c chia cho s\u1ed1 quan sa\u0301t tr\u01b0\u0300 m\u1ed9t.<\/p>\n

C\u0103n b\u1eadc hai c\u1ee7a ph\u01b0\u01a1ng sai \u0111\u1ec3 t\u00ecm \u0111\u1ed9 l\u1ec7ch chu\u1ea9n.<\/p>\n

S\u1eed d\u1ee5ng \u0111\u1ed9 l\u1ec7ch chu\u1ea9n<\/font><\/h3>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> l\u00e0 m\u1ed9t c\u00f4ng c\u1ee5 \u0111\u1eb7c bi\u1ec7t h\u1eefu \u00edch trong x\u00e2y d\u01b0\u0323ng chi\u1ebfn l\u01b0\u1ee3c \u0111\u1ea7u t\u01b0 hay trong giao d\u1ecbch v\u00ec n\u00f3 \u0111o l\u01b0\u1eddng m\u1ee9c \u0111\u1ed9 bi\u1ebfn \u0111\u1ed9ng c\u1ee7a th\u1ecb tr\u01b0\u1eddng v\u00e0 ch\u01b0\u0301ng khoa\u0301n, cu\u00f4\u0301i cu\u0300ng d\u1ef1 \u0111o\u00e1n hi\u1ec7u qua\u0309 \u0111a\u0300u t\u01b0.\u00a0<\/p>\n

Vi\u0301 du\u0323, nha\u0300 \u0111\u00e2\u0300u t\u01b0 c\u00e2\u0300n c\u00e2n nh\u0103\u0301c r\u0103\u0300ng c\u00e1c qu\u1ef9 t\u0103ng tr\u01b0\u1edfng t\u00edch c\u1ef1c th\u01b0\u01a1\u0300ng co\u0301 \u0111\u1ed9 l\u1ec7ch chu\u1ea9n cao h\u01a1n so v\u1edbi c\u00e1c ch\u1ec9 s\u1ed1 ch\u1ee9ng kho\u00e1n, v\u00ec c\u00e1c nh\u00e0 qu\u1ea3n l\u00fd danh m\u1ee5c \u0111\u1ea7u t\u01b0 c\u1ee7a h\u1ecd \u0111\u1eb7t c\u01b0\u1ee3c m\u01b0\u0301c ru\u0309i ro l\u01a1\u0301n h\u01a1n \u0111\u00ea\u0309 \u0111a\u0323t \u0111\u01b0\u01a1\u0323c l\u1ee3i nhu\u1eadn cao h\u01a1n m\u1ee9c trung b\u00ecnh.<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> th\u1ea5p h\u01a1n kh\u00f4ng nh\u1ea5t thi\u1ebft l\u00e0 t\u00f4\u0301t h\u01a1n ma\u0300 t\u1ea5t c\u1ea3 ph\u1ee5 thu\u1ed9c v\u00e0o kho\u1ea3n \u0111\u1ea7u t\u01b0 m\u00e0 nha\u0300 \u0111\u00e2\u0300u t\u01b0 \u0111ang co\u0301 v\u00e0 vi\u00ea\u0323c ho\u0323 co\u0301 s\u1eb5n s\u00e0ng ch\u1ea5p nh\u1eadn r\u1ee7i ro hay kh\u00f4ng. Khi co\u0301 s\u01b0\u0323 bi\u00ea\u0301n \u0111\u00f4\u0323ng trong danh m\u1ee5c \u0111\u1ea7u t\u01b0, c\u00e1c nh\u00e0 \u0111\u1ea7u t\u01b0 n\u00ean xem x\u00e9t kh\u1ea3 n\u0103ng ch\u1ecbu \u0111\u1ef1ng cu\u0309a c\u00e1 nh\u00e2n h\u1ecd \u0111\u1ed1i v\u1edbi s\u1ef1 bi\u1ebfn \u0111\u1ed9ng na\u0300y v\u00e0 m\u1ee5c ti\u00eau \u0111\u1ea7u t\u01b0 t\u1ed5ng th\u1ec3 c\u1ee7a h\u1ecd.\u00a0<\/p>\n

C\u00e1c nh\u00e0 \u0111\u1ea7u t\u01b0 \u01b0a thi\u0301ch ru\u0309i ro c\u00f3 th\u1ec3 tho\u1ea3i m\u00e1i v\u1edbi nh\u01b0\u0303ng chi\u1ebfn l\u01b0\u1ee3c \u0111\u1ea7u t\u01b0 va\u0300o ca\u0301c ta\u0300i sa\u0309n c\u00f3 \u0111\u1ed9 bi\u1ebfn \u0111\u1ed9ng cao h\u01a1n m\u1ee9c trung b\u00ecnh, trong khi c\u00e1c nh\u00e0 \u0111\u1ea7u t\u01b0 b\u1ea3o th\u1ee7 (hay e nga\u0323i ru\u0309i ro) thi\u0300 kh\u00f4ng.<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> l\u00e0 m\u1ed9t trong nh\u1eefng bi\u1ec7n ph\u00e1p \u0111o l\u01b0\u01a1\u0300ng r\u1ee7i ro c\u01a1 b\u1ea3n ch\u00ednh m\u00e0 c\u00e1c nh\u00e0 ph\u00e2n t\u00edch, qu\u1ea3n l\u00fd danh m\u1ee5c \u0111\u1ea7u t\u01b0, c\u1ed1 v\u1ea5n ta\u0300i chi\u0301nh s\u1eed d\u1ee5ng. M\u1ed9t \u0111\u00f4\u0323 ch\u00eanh l\u00ea\u0323ch l\u1edbn cho th\u1ea5y m\u1ee9c l\u1ee3i nhu\u1eadn c\u1ee7a m\u00f4\u0323t qu\u1ef9 \u0111ang ch\u00eanh l\u1ec7ch nhi\u00ea\u0300u so v\u1edbi m\u01b0\u0301c l\u1ee3i nhu\u1eadn d\u1ef1 ki\u1ebfn. Do ti\u0301nh ch\u00e2\u0301t d\u1ec5 hi\u1ec3u, c\u00f4ng cu\u0323 th\u00f4\u0301ng k\u00ea n\u00e0y th\u01b0\u1eddng xuy\u00ean \u0111\u01b0\u1ee3c s\u01b0\u0309 du\u0323ng \u0111\u00ea\u0309 b\u00e1o c\u00e1o cho c\u00e1c kh\u00e1ch h\u00e0ng v\u00e0 nh\u00e0 \u0111\u1ea7u t\u01b0.<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n so v\u1edbi ph\u01b0\u01a1ng sai<\/font><\/h3>\n

Ph\u01b0\u01a1ng sai \u0111\u01b0\u1ee3c ti\u0301nh b\u1eb1ng c\u00e1ch l\u1ea5y gi\u00e1 tr\u1ecb trung b\u00ecnh c\u1ee7a c\u00e1c quan sa\u0301t tr\u1eeb \u0111i gi\u00e1 tr\u1ecb trung b\u00ecnh, sau \u0111o\u0301 b\u00ecnh ph\u01b0\u01a1ng t\u1eebng k\u1ebft qu\u1ea3 n\u00e0y v\u00e0 cu\u00f4\u0301i cu\u0300ng l\u00e2\u0301y gi\u00e1 tr\u1ecb trung b\u00ecnh c\u1ee7a c\u00e1c k\u00ea\u0301t qua\u0309 n\u00e0y. \u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> l\u00e0 c\u0103n b\u1eadc hai c\u1ee7a ph\u01b0\u01a1ng sai.<\/p>\n

Ph\u01b0\u01a1ng sai gi\u00fap x\u00e1c \u0111\u1ecbnh \u0111\u00f4\u0323 da\u0300n tr\u1ea3i c\u1ee7a quan sa\u0301t khi so s\u00e1nh v\u1edbi gi\u00e1 tr\u1ecb trung b\u00ecnh. Ph\u01b0\u01a1ng sai l\u1edbn cho th\u00e2\u0301y c\u00f3 nhi\u1ec1u s\u1ef1 bi\u00ea\u0301n \u0111\u00f4\u0323ng trong c\u00e1c gi\u00e1 tr\u1ecb cu\u0309a t\u00e2\u0323p d\u1eef li\u1ec7u v\u00e0 c\u00f3 th\u1ec3 c\u00f3 kho\u1ea3ng c\u00e1ch l\u1edbn h\u01a1n gi\u1eefa gi\u00e1 tr\u1ecb ca\u0301c quan sa\u0301t v\u01a1\u0301i nhau. N\u1ebfu t\u1ea5t c\u1ea3 c\u00e1c\u00a0quan sa\u0301t \u0111\u01b0\u0301ng g\u1ea7n nhau, ph\u01b0\u01a1ng sai s\u1ebd nh\u1ecf h\u01a1n. Tuy nhi\u00ean, kha\u0301i ni\u00ea\u0323m na\u0300y kh\u00f3 hi\u00ea\u0309u h\u01a1n nhi\u00ea\u0300u so v\u1edbi \u0111\u1ed9 l\u1ec7ch chu\u1ea9n, do ph\u01b0\u01a1ng sai bi\u1ec3u th\u1ecb m\u1ed9t k\u1ebft qu\u1ea3 b\u00ecnh ph\u01b0\u01a1ng.<\/p>\n

\u0110\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> th\u01b0\u1eddng d\u1ec5 h\u00ecnh dung v\u00e0 d\u00ea\u0303 \u00e1p d\u1ee5ng h\u01a1n. \u0110\u1ed9 l\u1ec7ch chu\u1ea9n \u0111\u01b0\u1ee3c bi\u1ec3u th\u1ecb trong c\u00f9ng m\u1ed9t \u0111\u01a1n v\u1ecb \u0111o l\u01b0\u1eddng v\u1edbi d\u1eef li\u1ec7u, s\u1eed d\u1ee5ng \u0111\u1ed9 l\u1ec7ch chu\u1ea9n, c\u00e1c nh\u00e0 th\u1ed1ng k\u00ea c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh li\u1ec7u d\u1eef li\u1ec7u c\u00f3 ph\u00e2n ph\u00f4\u0301i chu\u00e2\u0309n<\/b> hay co\u0301 m\u1ed1i quan h\u1ec7 to\u00e1n h\u1ecdc kh\u00e1c.\u00a0<\/p>\n

N\u1ebfu d\u1eef li\u1ec7u co\u0301 m\u1ed9t ph\u00e2n ph\u00f4\u0301i chu\u00e2\u0309n, th\u00ec 68% quan sa\u0301t s\u1ebd n\u1eb1m trong m\u1ed9t bi\u00ean \u0111\u1ed9 l\u1ec7ch chu\u1ea9n \u0111\u00ea\u0301n \u0111i\u1ec3m trung vi\u0323 ho\u1eb7c trung b\u00ecnh. Ph\u01b0\u01a1ng sai do bi\u0300nh ph\u01b0\u01a1ng l\u00ean khi\u1ebfn nhi\u1ec1u \u0111i\u1ec3m d\u1eef li\u1ec7u n\u1eb1m ngo\u00e0i \u0111\u1ed9 l\u1ec7ch chu\u1ea9n, hay co\u0300n go\u0323i la\u0300 ca\u0301c \u0111i\u00ea\u0309m ngoa\u0323i lai. Ph\u01b0\u01a1ng sai nh\u1ecf h\u01a1n d\u1eabn \u0111\u1ebfn nhi\u1ec1u d\u1eef li\u1ec7u g\u1ea7n v\u1edbi gia\u0301 tri\u0323 trung b\u00ecnh.<\/p>\n

H\u1ea1n ch\u1ebf l\u1edbn nh\u1ea5t c\u1ee7a vi\u1ec7c s\u1eed d\u1ee5ng \u0111\u1ed9 l\u1ec7ch chu\u1ea9n l\u00e0 n\u00f3 c\u00f3 th\u1ec3 b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi c\u00e1c \u0111i\u00ea\u0309m ngoa\u0323i lai v\u00e0 c\u00e1c gi\u00e1 tr\u1ecb \u00e2m. \u0110\u1ed9 l\u1ec7ch chu\u1ea9n co\u0301 gi\u1ea3 \u0111\u1ecbnh la\u0300 ph\u00e2n ph\u1ed1i chu\u00e2\u0309n v\u00e0 xem t\u1ea5t c\u1ea3 s\u1ef1 kh\u00f4ng ch\u1eafc ch\u1eafn l\u00e0 r\u1ee7i ro, ngay c\u1ea3 khi n\u00f3 c\u00f3 l\u1ee3i cho nh\u00e0 \u0111\u1ea7u t\u01b0, v\u00ed d\u1ee5 nh\u01b0 khi l\u1ee3i nhu\u1eadn \u0111a\u0323t m\u01b0\u0301c tr\u00ean trung b\u00ecnh.<\/p>\n

V\u00ed d\u1ee5 v\u1ec1 \u0111\u1ed9 l\u1ec7ch chu\u1ea9n<\/font><\/h3>\n

Gi\u1ea3 s\u1eed ch\u00fang ta c\u00f3 c\u00e1c quan sa\u0301t 5, 7, 3 v\u00e0 7, t\u1ed5ng c\u1ed9ng 22. Sau \u0111\u00f3, b\u1ea1n s\u1ebd chia 22 cho s\u1ed1 quan sa\u0301t, trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y la\u0300 4 \u0111\u01b0\u01a1\u0323c 5,5. Ta co\u0301 trung bi\u0300nh la\u0300: x\u0304 = 5,5 v\u00e0 N = 4.<\/p>\n

Ph\u01b0\u01a1ng sai<\/b> \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1eb1ng c\u00e1ch tr\u1eeb m\u00f4\u0303i quan sa\u0301t cho gi\u00e1 tr\u1ecb trung b\u00ecnh, ta \u0111\u01b0\u01a1\u0323c l\u00e2\u0300n l\u01b0\u01a1\u0323t ca\u0301c k\u00ea\u0301t qua\u0309 la\u0300 -0,5, 1,5, -2,5 v\u00e0 1,5. M\u1ed7i gi\u00e1 tr\u1ecb na\u0300y sau \u0111\u00f3 \u0111\u01b0\u1ee3c b\u00ecnh ph\u01b0\u01a1ng, b\u0103\u0300ng 0,25, 2,25, 6,25 v\u00e0 2,25. C\u00f4ng c\u00e1c gi\u00e1 tr\u1ecb b\u00ecnh ph\u01b0\u01a1ng sau \u0111\u00f3 chia cho gi\u00e1 tr\u1ecb N tr\u1eeb 1, b\u1eb1ng 3, cho k\u00eat qua\u0309 ph\u01b0\u01a1ng sai x\u1ea5p x\u1ec9 3,67.<\/p>\n

C\u0103n b\u1eadc hai c\u1ee7a ph\u01b0\u01a1ng sai co\u0301 \u0111\u1ed9 l\u1ec7ch chu\u1ea9n<\/b> l\u00e0 kho\u1ea3ng 1.915.<\/p>\n

Vi\u0301 du\u0323 v\u00ea\u0300 \u0111\u00f4\u0323 l\u00ea\u0323ch chu\u00e2\u0309n trong \u0111\u00e2\u0300u t\u01b0 ta\u0300i chi\u0301nh, xem x\u00e9t c\u1ed5 phi\u1ebfu c\u1ee7a Apple (AAPL) trong n\u0103m n\u0103m qua th\u00e2\u0301y \u0111\u01b0\u01a1\u0323c l\u1ee3i nhu\u1eadn cho AAPL l\u00e0 37,7% cho n\u0103m 2014, -4,6% cho n\u0103m 2015, 10% cho , 46,1% cho v\u00e0 -6,8% cho . L\u1ee3i nhu\u1eadn trung b\u00ecnh trong n\u0103m n\u0103m l\u00e0 16,5%.<\/p>\n

L\u00e2\u0301y l\u01a1\u0323i nhu\u00e2\u0323n c\u1ee7a m\u1ed7i n\u0103m tr\u01b0\u0300 gi\u00e1 tr\u1ecb trung b\u00ecnh \u0111\u01b0\u01a1\u0323c 21,2%, -21,2%, -6,5%, 29,6% v\u00e0 -23,3%. T\u1ea5t c\u1ea3 c\u00e1c gi\u00e1 tr\u1ecb n\u00e0y sau \u0111\u00f3 \u0111\u01b0\u1ee3c b\u00ecnh ph\u01b0\u01a1ng \u0111\u01b0\u01a1\u0323c 449.4, 449.4, 42.3, 876.2 v\u00e0 542.9. Ti\u0301nh \u0111\u01b0\u01a1\u0323c ph\u01b0\u01a1ng sai l\u00e0 590.1, sau \u0111\u00f3 c\u00e1c gi\u00e1 tr\u1ecb b\u00ecnh ph\u01b0\u01a1ng \u0111\u01b0\u1ee3c c\u1ed9ng l\u1ea1i v\u1edbi nhau v\u00e0 chia cho 4 (N – 1). C\u0103n b\u1eadc hai c\u1ee7a ph\u01b0\u01a1ng sai \u0111\u01b0\u1ee3c l\u1ea5y \u0111\u1ec3 c\u00f3 \u0111\u1ed9 l\u1ec7ch chu\u1ea9n l\u00e0 24,3%.\u00a0<\/p>\n

(Theo Investopedia<\/i>)<\/p>\n<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

\n \u0110\u1ed9 l\u1ec7ch chu\u1ea9n (ti\u00ea\u0301ng Anh: Standard Deviation) l\u00e0 m\u1ed9t c\u00f4ng cu\u0323 th\u1ed1ng k\u00ea \u0111o l\u01b0\u01a1\u0300ng \u0111\u1ed9 ph\u00e2n t\u00e1n c\u1ee7a t\u1eadp d\u1eef li\u1ec7u so v\u1edbi gi\u00e1 tr\u1ecb trung b\u00ecnh c\u1ee7a n\u00f3 v\u00e0 \u0111\u01b0\u1ee3c t\u00ednh l\u00e0 c\u0103n b\u1eadc hai c\u1ee7a ph\u01b0\u01a1ng sai.\n <\/div>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[417],"tags":[],"_links":{"self":[{"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/posts\/31486"}],"collection":[{"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/comments?post=31486"}],"version-history":[{"count":0,"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/posts\/31486\/revisions"}],"wp:attachment":[{"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/media?parent=31486"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/categories?post=31486"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/masterskills.org\/blog\/wp-json\/wp\/v2\/tags?post=31486"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}