The use of the word "that" when the word "than" should be used.

"That" is a pronoun (ignoring the use of "that" to introduce a subordinate clause) and, as such, is used to designate or describe a particular item. "Than" is a conjunction, used when comparing two items. Example: "I want the glass that is blue" v. "My glass is bigger than your glass."

Basic grammar!

Next week: the difference between "that" and "which."