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 sample standard deviation?
A) 1.177
B) 6.6
C) 1.385
D) 7.6

Question

Quizplus · Accepted Answer

The sample standard deviation is 1.177 pounds. This can be calculated using the formula:s = sqrt(sum((x - mean)^2) / (n - 1))where:s is the sample standard deviationx is each data pointmean is the sample meann is the sample sizeIn this case, the sample mean is 7.6 pounds. Plugging the data into the formula, we get:s = sqrt((9.0 - 7.6)^2 + (7.3 - 7.6)^2 + (6.0 - 7.6)^2 + (8.8 - 7.6)^2 + (6.8 - 7.6)^2 + (8.4 - 7.6)^2 + (6.6 - 7.6)^2) / (7 - 1))s = sqrt(1.44 + 0.09 + 3.24 + 1.44 + 0.64 + 0.64 + 1.00) / 6s = sqrt(8.49) / 6s = 1.177 pounds

A Hypothesis Regarding the Weight of Newborn Infants at a Community