1. The problem is to determine the best type of graph to show the change of temperature over a week. 2. When showing changes over time, the most common and effective graph type is a line graph. 3. A line graph connects data points with lines, making it easy to see trends and fluctuations over the days. 4. Each point on the graph represents the temperature at a specific day, and the line shows how temperature changes from day to day. 5. Other graph types like bar graphs or pie charts are less effective for showing continuous changes over time. 6. Therefore, a line graph is best to visualize temperature changes over a week.