Question

The historical data of Velvetta Inc., a healthcare products manufacturer, have shown that in a production process for filling bottles of shampoo, variance in the volume is constant; however, clogs in the filling machine often affect the average volume. The historical standard deviation is 11 milliliters. In filling 250-milliliter bottles, a sample of 40 found an average volume of 248 milliliters.

Velvetta Inc. Shampoo Production

alpha	0.05
s	11
n	40
xbar	248

From the table above, calculate zα/2 value at a 95% confidence interval

a. 1.96

b. 2.19

c. 1.64

d. 1.84

Answer 1