A method for operating a memory includes: receiving an active command and a row address; confirming that a portion of columns of a first row corresponding to the row address is replaced with a portion of columns of a second row; activating the first row and the second row; confirming activation of a random pulse; randomly selecting one among the row address corresponding to the first row and a row address corresponding to the second row in response to the activation of the random pulse; and sampling the selected row address as a sampling address.