Find the range for the group of data items. \[ 15,18,18,24 \] The range is $\square$.

Step 1 ：Define the data as [15,18,18,24].

Step 2 ：Calculate the range by subtracting the smallest value from the largest value.

Step 3 ：The range is the difference between the maximum and minimum values in the data set.

Step 4 ：Using the data set [15,18,18,24], the maximum value is 24 and the minimum value is 15.

Step 5 ：Subtract the minimum value from the maximum value to find the range: \(24 - 15 = 9\).

Step 6 ：Final Answer: The range is \(\boxed{9}\).