A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. What is the decision for a statistical significant change in average weights at birth at the 5% level of significance?
A) Fail to reject the null hypothesis.
B) Reject the null hypothesis and conclude the mean is higher than 6.6 lb.
C) Reject the null hypothesis and conclude the mean is lower than 6.6 lb.
D) Cannot calculate because the population standard deviation is unknown.

Question

Quizplus · Accepted Answer

The sample mean is 7.27 pounds, which is higher than 6.6 pounds. However, with a small sample size of 7, the variability is high, and without further statistical testing (like a t-test), we cannot conclude a significant change at the 5% level. Therefore, we fail to reject the null hypothesis.

A Hypothesis Regarding the Weight of Newborn Infants at a Community