Answer :
Final answer:
The interquartile range (IQR) is calculated by subtracting the first quartile (Q1) from the third quartile (Q3), and it describes the range of the middle 50 percent of a data set.
Explanation:
The interquartile range (IQR) is a measure of variability that is used to capture the spread of the middle 50 percent of data in a data set. The correct way to calculate the interquartile range is by finding the difference between the third quartile (Q3) and the first quartile (Q1). So, the formula for IQR is IQR = Q3 - Q1. This calculation excludes the highest and lowest quarters of data, focusing on the central spread of the dataset. Quartiles are specific percentiles. Specifically, Q1 corresponds to the 25th percentile and Q3 corresponds to the 75th percentile.
In the given options, the correct answer is c) quartile 3 (Q3) minus quartile 1 (Q1). For instance, if Q3 is 9 and Q1 is 2, then the IQR is calculated as 9 minus 2, giving an IQR of 7. The IQR helps to determine the dispersion of the data and identify potential outliers.
