A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 71 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 6.1, 8.1, 9.1, 10.1, 71, 11.1, and 12.1 pounds. If a = 0.200, what is the critical value? The population standard deviation is Unknown.
a) 0
b) +/- 936
c) +/- 1.358
d) +1.440