1rBTX 06. ESTADÍSTICA/1.6.3 Bidimensional 1.6.3.25Q InterpretaCoefCorrel S'estudia la relació entre les variables X_i i Y_i a partir dels resultats següents:

X_i	Y_i
#x1	#y1
#x2	#y2
#x3	#y3
#x4	#y4
#x5	#y5

Fes servir l'Excel per fer els càlculs (arrodoneix als centèsims)

a).Calcula la mitjana de X_i

b) Calcula la mitjana de Y_i

c) Calcula la covariància «math xmlns=¨http://www.w3.org/1998/Math/MathML¨»«msub mathcolor=¨#7F007F¨»«mi mathvariant=¨bold¨ mathcolor=¨#7F007F¨»§#963;«/mi»«mi mathvariant=¨bold¨»xy«/mi»«/msub»«/math»

d) Calcula el coeficient de correlació (Pearson) r
e) Classifica la correlació {D,d}. D per directa, I per inversa, F per forta i d per dèbil. Directa si és positiva, indirecta si és negativa. Forta si, en valor absolut, és més gran que 0.5, feble en cas contrari.

]]> 1.0000000 0.3333333 0 0 a) X¯=#hb) Y¯=#nc) σxy=#cd) r = #pe) Tipus =#sol]]> <question><wirisCasSession><![CDATA[<session lang="ca" version="2.0"><library closed="false"><mtext style="color:#ffc800" xml:lang="ca">variables</mtext><group><command><input><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x1</mi><mo>=</mo><mn>10</mn><mo>*</mo><mi>aleatori</mi><mo>(</mo><mn>2</mn><mo>,</mo><mn>5</mn><mo>)</mo></math></input></command><command><input><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x2</mi><mo>=</mo><mi>x1</mi><mo>+</mo><mi>aleatori</mi><mo>(</mo><mn>5</mn><mo>,</mo><mn>10</mn><mo>)</mo></math></input></command><command><input><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x3</mi><mo>=</mo><mi>x2</mi><mo>+</mo><mi>aleatori</mi><mo>(</mo><mn>5</mn><mo>,</mo><mn>10</mn><mo>)</mo></math></input></command><command><input><math 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