In the US, 77% of all teens have a TV in their bedrooms, while 59% of all teens in Spain have them. A simple random sample of 500 teens from the US and 300 from Spain are selected and all are asked whether they have a TV in their bedrooms. Let be the difference in the sample proportions of teens with a TV in their bedrooms, where is the sample proportion of US teens with a TV in their bedrooms and is the sample proportion of Spanish teens with a TV in their bedrooms. What is the shape of the sampling distribution of the difference in the two sample proportions?