Respuesta :

Answer:

Step-by-step explanation:

3,9,12,(15),16,18,21

   

mean (middle number) = 15

Q1 = 9.....the middle number of the numbers before the mean

Q3 = 18...the middle number of the numbers after the mean

interquartile range (IQR) = Q3 - Q1 = 18 - 9 = 9 <==