the average price of a gallon of gas was $3.22 and 2014 and $2.40 in 2015 what is the percent decrease in the price of gas​

The graph of fx shown below has the same shape as the graph of gx = 3x^2 but is shifted down 2 units

()1. how do you find range? 2.the following set of data is to be organized into a histogram. if there are to be five intervals on the graph, what should the length of each interval be? 30, 34, 23, 21, 27, 25, 29, 29, 25, 23, 32, 31

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?