XÁC SUẤT THỐNG KÊ " CHƯƠNG 6 LÝ THUYẾT TƯƠNG QUAN VÀ HÀM HỒI QUY"

... 1 1 1 1 3 2 9 6 4 4 4 16 16 16 6 4 36 24 16 8 5 64 40 25 9 7 81 63 49 11 8 121 88 64 14 9 1 96 1 26 81  x = 56  y = 40  x 2 = 524  xy = 364  y 2 = 2 56 Hˆe . s ´ ˆo t ’ u ’ ong quan c ’ ua X ... 2080 16 160 2 56 2 560 13 114 169 1482 20 142 400 2840 24 265 5 76 6 360  x = 165  y = 1334  x 2 = 3855  xy = 2 961 1 Ta c´o a = n(  xy) − (  x)(  y) n(  x 2 ) − (  x) 2 = 8(1 961 1) − ( 165 )(1334) ... −0, 30 96. 3. y x = 0, 67 x + 7, 18, σ 2 = 1, 1 26, (0, 62 80 ; 0, 71 76) . 4. a) y x = 0, 7018x − 61 , 5537, b) x y = 0, 91y + 112, 96. 5. r = 0, 8 165 ; y x = 0, 017x + 0, 562 2. 6. a) r = 0, 69 , b)...

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... 1 1 1 13 2 9 6 44 4 16 16 16 6 4 36 24 16 8 5 64 40 259 7 81 63 4911 8 121 88 64 14 9 1 96 1 26 81x = 56 y = 40x2= 524xy = 364 y2= 2 56 Hˆe.s´ˆo t’u’ong quan c’ua X ... 2080 16 160 2 56 2 560 13 114 169 148220 142 400 284024 265 5 76 6 360 x = 165 y = 1334x2= 3855xy = 2 961 1Ta c´oa =n(xy) − (x)(y)n(x2) − (x)2=8(1 961 1) − ( 165 )(1334)8(3855)( 165 )2= 167 78 361 5= ... −0, 30 96. 3. yx= 0, 67 x + 7, 18, σ2= 1, 1 26, (0, 62 80 ; 0, 71 76) .4. a) yx= 0, 7018x − 61 , 5537, b) xy= 0, 91y + 112, 96. 5. r = 0, 8 165 ; yx= 0, 017x + 0, 562 2. 6. a) r = 0, 69 , b)...

... nhiˆen r ` ’ oi ra . c c´o phˆan ph ´ ˆoi x´ac su ´ ˆat cho b ’ ’ oi: X 1 2 3 4 5 6 P 1 6 1 6 1 6 1 6 1 6 1 6 1.3 D ¯ a . i l ’ u ’ o . ng ng ˜ ˆau nhiˆen liˆen tu . c v`a h`am mˆa . t ¯dˆo . ... < x ≤ 6 1 ; x > 6 • V´ı du . 6 Cho X l`a ¯da . i l ’ u ’ o . ng ng ˜ ˆau nhiˆen liˆen tu . c c´o h`am mˆa . t ¯dˆo . f(x) =      0 n ´ ˆeu x < 0 6 5 x n ´ ˆeu 0 ≤ x ≤ 1 6 5x 4 n ... Ta c´o E(X 2 ) = ∞  −∞ x 2 f(x)dx = 3  0 x 2 4 81 x 3 dx = 4 81  x 6 6  3 0 = 6 Vˆa . y V ar(X) = E(X 2 ) − [E(X)] 2 = 6 − (2, 4) 2 = 0, 24. ✸ T´ınh ch ´ ˆat i) Var(C)=0; (C khˆong ¯d ’ ˆoi)....

... 284024 265 5 76 6 360 x = 165 y = 1334x2= 3855xy = 2 961 1Ta c´oa =n(xy) − (x)(y)n(x2) − (x)2=8(1 961 1) − ( 165 )(1334)8(3855)( 165 )2= 167 78 361 5= 4, 64 b = y − ax =13348− 167 78 361 5 165 8= 71Vˆa.y ... 16 16 13 20 24Y 145 228 150 130 160 114 142 265 Gi’aiTa lˆa.p b’ang sauxiyix2ixiyi15 145 225 317538 228 1444 866 423 150 529 3450 16 130 2 56 2080 16 160 2 56 2 560 13 114 169 148220 142 400 284024 265 ... 24 168 5 64 40 259 7 81 63 4911 8 121 88 64 14 9 1 96 1 26 81x = 56 y = 40x2= 524xy = 364 y2= 256Hˆe.s´ˆo t’u’ong quan c’ua X v`a Y l`arXY=nxy − (x)(y)n(x2) − (x)2.n(y2) − (y)2=8. 364 ...