def update_col_types(frame):
    """Returns a new DataFrame with the column types replaced with int64 for
       population columns and string for other columns.

       frame: The original DataFrame"""
    colTypes = {}
    for col in frame.columns:
        if col != "NAME" and col != "state" and col != "county":
            colTypes[col] = "int64"
        else:
            colTypes["state"] = "string"
    frame = frame.astype(colTypes)
    return frame