Final answer:
Monthly mean temperatures are not merely averages of the highest and lowest temperatures of the month; they are computed from the average of the daily mean temperatures over the entire month. Time series analysis of temperature data offers a complete picture, avoiding reliance on extreme values alone.
Step-by-step explanation:
The statement that monthly mean temperatures are made by taking the average of the highest and lowest temperatures of the month is false. Monthly mean temperatures are usually calculated by taking the average of the daily mean temperatures throughout the month. The daily mean temperature is typically determined by calculating the mean of the daily high and daily low temperatures, or by more sophisticated methods that involve hourly temperature data. Time series graphs can represent the temperature changes over a month and provide a visual representation of the pattern of data over time.
When studying changes in temperature, it's important to consider the complete data, not just extreme weather patterns. For example, to understand the typical weather pattern in a place like Chicago, Illinois, one would need to observe a range of data over time rather than focus solely on the record highest and lowest recorded temperatures.