When testing μ, how do we decide whether to use the standard normal distribution or a Student's t distribution? If the x distrib
ution is normal and n ≥ 30 with known σ we use the Student's t. With the same conditions and unknown σ we use the standard normal. If the x distribution is normal and n ≥ 20 with known σ we use the standard normal. With the same conditions and unknown σ we use the Student's t. If the x distribution is normal and n ≥ 30 with known σ we use the standard normal. With the same conditions and unknown σ we use the Student's t. Whenever we assume the populations are independent, we always use the standard normal.
So this is a oddly phrased question but I believe I understand it. You need to find 10 percent of 1170 grams and that it 117. And for you information I did use calculator to prevent error so don't worry about that.
