You have been hired by the Regional Real Estate Company to help...

You have been hired by the Regional Real Estate Company to help them analyze real estate data. One of the company's Pacific region salespeople just returned to the office with a newly designed advertisement. The average cost per square foot of home sales based on this advertisement is $280. The salesperson claims that the average cost per square foot in the Pacific region is less than $280. In other words, he claims that the newly designed advertisement would result in higher average cost per square foot in the Pacific Region. He wants you to make sure he can make that statement before approving the use of the advertisement. In order to test his claim, you will generate a random sample of size 750 houses using data for the Pacific region and use this data to perform a hypothesis test. 

Is the null hypothesis ( u = 280) and the alternative hypothesis (u < 280) or is the alternative hypothesis (u > 280)?

Also, would it be a right-tailed test or a left-tailed test?