100 students in the gym 25 are wearing a hat, 25 are wearing a T- shirt, 25 are wearing a hoodie and 25 are wearing a yankee T-shirt. If one student is randomly selected what is the probability that student is wearing a hat.

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.