To determine the number of modes in the dataset, we first need to count the frequency of each item:
- t-shirt: 3
- pants: 1
- sweater: 5
- socks: 2
The mode is the item that appears most frequently in the dataset. Here, the item "sweater" occurs the most, with a frequency of 5.
Since there is only one item that appears most frequently, the dataset has a single mode.
Thus, the answer is:
1