Final answer:
To calculate the IQR, identify the first and third quartiles (Q1 and Q3) from the ordered data set or a box plot on a dot plot, then subtract Q1 from Q3.
Step-by-step explanation:
To find the interquartile range (IQR) of data from a dot plot, first we need to identify the first quartile (Q1) and the third quartile (Q3). The IQR is then calculated by subtracting Q1 from Q3. The data values must be ordered from least to greatest to identify the quartiles correctly. If the dot plot provided shows clear quartile points or includes a box plot, we identify Q1 and Q3 from these markers. Otherwise, we use the rank-ordered data set to calculate the positions of Q1 and Q3 by using the appropriate percentile positions. Once Q1 and Q3 are found, the difference between these two numbers will give us the IQR, providing an insight into the spread of the middle 50 percent of the data set.