Scenario 1. A researcher wants to investigate whether "doom scrolling" increases anxiety among college students. Doom scrolling refers to the habit of consuming an excessive amount of negative news and distressing content on social media or other online platforms. She randomly assigns participants to either engage in 20 minutes of doom scrolling each day for 2 weeks, or to scroll through neutral social media content for 20 minutes each day for 2 weeks. She then measures their feelings of anxiety what is the null hypothesis for scenario 1 in statistical terms