Your watch says you had three hours of deep sleep. Should you believe it? Millions of people rely on phone apps and wearable devices like rings, smartwatches and sensors to monitor how well they're sleeping, but these trackers don't necessarily measure sleep directly.
With a winter storm blanketing a large swath of the country, Hollywood had its quietest weekend of the year at the box office. The Amazon MGM sci-fi thriller "Mercy" dethroned "Avatar: Fire and Ash" from the No. 1 spot with $11.2 million in North America, according to studio estimates Sunday.