40 lines
1,017 B
Text
40 lines
1,017 B
Text
func eval a b c x .
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return a + (b + c * x) * x
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.
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proc regression xa[] ya[] .
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n = len xa[]
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for i = 1 to n
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xm = xm + xa[i]
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ym = ym + ya[i]
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x2m = x2m + xa[i] * xa[i]
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x3m = x3m + xa[i] * xa[i] * xa[i]
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x4m = x4m + xa[i] * xa[i] * xa[i] * xa[i]
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xym = xym + xa[i] * ya[i]
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x2ym = x2ym + xa[i] * xa[i] * ya[i]
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.
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xm = xm / n
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ym = ym / n
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x2m = x2m / n
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x3m = x3m / n
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x4m = x4m / n
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xym = xym / n
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x2ym = x2ym / n
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#
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sxx = x2m - xm * xm
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sxy = xym - xm * ym
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sxx2 = x3m - xm * x2m
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sx2x2 = x4m - x2m * x2m
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sx2y = x2ym - x2m * ym
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#
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b = (sxy * sx2x2 - sx2y * sxx2) / (sxx * sx2x2 - sxx2 * sxx2)
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c = (sx2y * sxx - sxy * sxx2) / (sxx * sx2x2 - sxx2 * sxx2)
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a = ym - b * xm - c * x2m
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print "y = " & a & " + " & b & "x + " & c & "x^2"
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numfmt 3 0
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for i = 1 to n
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print xa[i] & " " & ya[i] & " " & eval a b c xa[i]
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.
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.
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xa[] = [ 0 1 2 3 4 5 6 7 8 9 10 ]
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ya[] = [ 1 6 17 34 57 86 121 162 209 262 321 ]
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regression xa[] ya[]
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