Question 716456
Lower Limit: 


L = mean - za/2 * (standard deviation)/sqrt(n)


L = 30 - 1.96 * (8)/sqrt(100)


L = 30 - 1.96 * (8)/10


L = 30 - 1.96 * 0.8


L = 30 - 1.568


L = 28.432



Upper Limit: 


U = mean + za/2 * (standard deviation)/sqrt(n)


U = 30 + 1.96 * (8)/sqrt(100)


U = 30 + 1.96 * (8)/10


U = 30 + 1.96 * 0.8


U = 30 + 1.568


U = 31.568




So the 95% confidence interval is (L, U) = (28.432, 31.568)


Round this to one decimal place to get (28.4, 31.6)


So the answer is <font color="red">Choice A) between 28.4 and 31.6</font>