1. what is the mean change in the forecasted high temperatures over the next 7 days?

For this question you will have to find your own set of data for your area, just go to weather.com or a similar site and make a set of temperatures for the next 7 days in your area. The mean can be found by adding all temperatures, then dividing their sum by the number of objects being added. 
For example, if my set of temperatures were {75, 90, 83, 77, 91, 88, 80}, I would find the mean with the equation (75 + 90 + 83 + 77 + 91 + 88 + 80)/7, or 83.4