Interquartile range : The interquartile range formula is the first quartile subtracted from the third quartile: IQR = Q3 – Q1.
For the brand A: Q1 = 70 and Q3 = 80
Interquartile range for the brand A = Q3 - Q1
= 80 - 70
= 10
For the brand B: Q1 = 65 and Q3 = 85
Interquartile range for the brand B = Q3 - Q1
= 85 - 65
= 20
Thus, the IQR range for brand A $10, is less than the IQR of brand B $20
Answer : B) The IQR range for brand A $10, is less than the IQR of brand B $20