Q. 71 - The Practice of Statistics for AP

Question

How heavy a load (pounds) is needed to pull apart pieces of Douglas fir $4$ inches long and $1.5$ inches square? A random sample of $20$ similar pieces of Douglas fir from a large batch was selected for a science class. The Fathom boxplot below shows the class’s data. Explain why it would not be wise to use a one-sample t interval to estimate the population mean $\mu$.

Step-by-Step Solution

Answer

The Normal requirement to use the $t$-procedure is thus not required.

Step 1: Given Information

Step 2: Explanation

In the box plot we note that there are $3$ outliers and the distribution appears to be left-skewed (since the line in the box of the boxplot is more to the right of the box).

Since the distribution contains outliers and skewness, the distribution is NOT approximately a normal distribution.