Algebra-1

To find the interquartile range IQR, we need to determine the first quartile Q1 and the third quartile Q3.  

1. Step 1: Order the data already ordered  
  4, 5, 6, 7, 7, 8, 9, 10, 11, 12  

2. Step 2: Find the median Q2:  
  Median = 7 + 8/2 = 7.5  

3. Step 3: Find Q1 lower half median:  
  Lower half: 4, 5, 6, 7, 7  
  Q1 = 6  

4. Step 4: Find Q3 upper half median:  
  Upper half: 8, 9, 10, 11, 12  
  Q3 = 10  

5. Step 5: Calculate the IQR:  

 

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