please help me please and explain

Lower Quartile Explanation: Arrange the terms in ascending order
20, 22, 25, 28, 29, 30, 32, 33, 34
Take the lower half of the ascending set: 20, 22, 25, 28
Find the median of 20, 22, 25, 28: 23.5
Upper Quartile Explanation: Arrange the terms in ascending order
20, 22, 25, 28, 29, 30, 32, 33, 34
Take the upper half of the ascending set: 30, 32, 33, 34
Find the median of 30, 32, 33, 34: 32.5
Interquartile Explanation:
Compute the first quartile of the list: 23.5
Compute the third quartile of the list: 32.5
Compute the difference between 32.5 and 23.5: 9