Qual a média, a variância e o desvio padrão da população: 4,0; 5,0; 6,0; 7,0; 8,0 e de sua respectiva distribuição amostral de médias?

Notas: { 4,0; 5,0; 6,0; 7,0; 8,0 }

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1) Média (m): como há n = 5 notas, o valor de m é:

-> m = (4,0 + 5,0 + 6,0 + 7,0 + 8,0) / n

-> m = (4,0 + 5,0 + 6,0 + 7,0 + 8,0) / 5

-> m = (30,0) / 5

-> m = 6,0

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2) Variância (v): com n = 5 e m = 6,0, o valor de v é:

-> v = [ (4,0 - m)² + (5,0 - m)² + (6,0 - m)² + (7,0 - m)² + (8,0 - m)² ] / n

-> v = [ (4,0 - 6,0)² + (5,0 - 6,0)² + (6,0 - 6,0)² + (7,0 - 6,0)² + (8,0 - 6,0)² ] / 5

-> v = [ (-2)² + (-1)² + (0)² + (1)² + (2)² ] / 5

-> v = [ 4 + 1 + + 1 + 4 ] / 5

-> v = [ 10 ] / 5

-> v = 2

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3) Desvio padrão (Dp): com variância v = 2, o valor de Dp é:

-> Dp = √v

-> Dp = √2

-> Dp = 1,414

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