Question: Newborn baby has extremely low birth weight (ELBW) if it weighs less than 1000 grams. A study of the health of such children in later years examined a random sample of 219 children. Their mean weight at birth was x¯ = 810 grams. This sample mean is an unbiased estimator of the mean weight m in the population of all ELBW babies, which means that
(a) in all possible samples of size 219 from this population, the mean of the values of x¯ will equal 810.
(b) in all possible samples of size 219 from this population, the mean of the values of x¯ will equal μ.
(c) as we take larger and larger samples from this population, x¯ will get closer and closer to m.
(d) in all possible samples of size 219 from this population, the values of x¯ will have a distribution that is close to Normal.
(e) the person measuring the children's weights does so without any error.