Hi, We made an experiment in class where we measured the evolution of temperature over the course of 5 weeks. I'd like to show that the increase in temperature is accelerating as summer is coming. Is it enough to calculate the slope of the linear trend over the full 5 weeks and show that it is smaller than the slope of the linear trend over the past week (increase in trends) to deduce that it is accelerating ? I'm asking because my teacher said that comparing linear trends over different time periods is not always appropriate and can be biased, but i don't understand why. Thanks.