To determine the upper boundary for outliers in a box plot, follow these steps:
1. Identify the first quartile (Q1) and the third quartile (Q3):
- In this problem, the first quartile [tex]\( Q1 = 3.5 \)[/tex] inches.
- The third quartile [tex]\( Q3 = 6.0 \)[/tex] inches.
2. Calculate the interquartile range (IQR):
- The interquartile range (IQR) is the difference between the third quartile and the first quartile.
- [tex]\( \text{IQR} = Q3 - Q1 \)[/tex].
So, [tex]\( \text{IQR} = 6.0 - 3.5 = 2.5 \)[/tex] inches.
3. Determine the upper boundary for outliers:
- The formula to find the upper boundary for outliers is [tex]\( \text{Upper Boundary} = Q3 + 1.5 \times \text{IQR} \)[/tex].
- Substituting the values into the formula:
[tex]\( \text{Upper Boundary} = 6.0 + 1.5 \times 2.5 \)[/tex]
[tex]\( = 6.0 + 3.75 = 9.75 \)[/tex] inches.
Therefore, the smallest value beyond which you will find outliers is [tex]\( 9.75 \)[/tex] inches.
Correct answer: A. 9.75 in.