Question

Grandma Gertrude's Chocolates, a family owned business, has an opportunity to supply its product for distribution through a large coffee house chain. However, the coffee house chain has certain specifications regarding cacao content as it wishes to advertise the health benefits (antioxidants) of the chocolate products it sells. In order to determine the mean % cacao in its dark chocolate products, quality inspectors sample 36 pieces. They find a sample mean of 55% with a standard deviation of 4%. The correct value of t* to construct a 90% confidence interval for the true mean % cacao is ________.

Answer 1

t-value = 1.690

Explanation:

We are given;

Sample size; n = 36

DF = n - 1

DF = 36 - 1

DF = 35

Confidence level = 90%

However, from the first table I attached, we see that the critical significance level of a 90% Confidence level is 0.05

Thus, in the second table, looking at a DF of 35 and significance level of 0.05, we have a critical t-value = 1.690