The mean weight of babies born in a hospital last year was 2.84 kg.Suppose the standard deviation of the weights is 0.95 kg.Which would be more unusual,a baby weighing 1.8 kg or a baby weighing 3.83 kg? Explain.
A)A 1.8 kg baby is more unusual (z = -1.09)compared with a 3.83 kg baby (z = 1.04).
B)A 3.83 kg baby is more unusual (z = 1.90)compared with a 1.8 kg baby (z = 4.05).
C)A 3.83 kg baby is more unusual (z = -1.09)compared with a 1.8 kg baby (z = -1.09).
D)A 1.8 kg baby is more unusual (z = -1.05)compared with a 3.83 kg baby (z = -1.04).
E)A 3.83 kg baby is more unusual (z = 1.04)compared with a 1.8 kg baby (z = -1.09).

Question

Quizplus · Accepted Answer

To determine which baby is more unusual, we need to calculate the z-scores for each weight. For a 1.8 kg baby, the z-score is (1.8-2.84)/0.95 = -1.09. For a 3.83 kg baby, the z-score is (3.83-2.84)/0.95 = 1.04. A negative z-score indicates that the weight is below average, while a positive z-score indicates that the weight is above average. Since the z-score for the 1.8 kg baby is further from zero than the z-score for the 3.83 kg baby, the 1.8 kg baby is more unusual. Therefore, the best choice is A.

The Mean Weight of Babies Born in a Hospital Last