In the past six months, Luke's take-home income increased from $4,000 per month to $5,000 per month (an increase of 25%). While on vacation, Luke encouraged his wife to buy some new jewelry. Normally, his wife would only buy one item of jewelry while on vacation. However, this time she purchased four items of jewelry (an increase of 300%). The income elasticity calculated using the formula for income elasticity is __________ and the jewelry items are a __________ good