Does the day a house is listed for sale affect how long it takes for the sale to be completed or its selling price? A study conducted by economists attempted to answer the question. A random sample of houses that sold in a major city was studied. The number of days between the listing and the sale was recorded as well as the day of the week the listing started.

a. Is there enough evidence to conclude that differences in the number of days until the sale is made exist between the seven days?

b. If there are differences which days differ?