The Amityville Horror is purported to be a real story. The Lutz family's account of their time in that house is what made it famous. They had some really spooky things happen. For example, they said there were slime - like substances on the walls and that furniture moved on its own. But there are also many who think the family made it all up to get money from book deals and movies. So, it's hard to say for sure if it's real.
The Alexa horror story is likely not real. These kinds of tales often spread through word-of-mouth or the internet and are exaggerated or fabricated to capture people's attention.
The Amityville Horror story has elements that are said to be real, but it's also been embellished and sensationalized over time. So, it's a bit of a mix of fact and fiction.
I'm not sure if the 'real dandupalya story' is a horror story. Without knowing the details of the story, it's difficult to classify it in a particular genre.
I don't know for sure. Just because it's called 'flight 7500 real story' doesn't necessarily mean it's a horror story. It could be a true account of a normal flight with some interesting events that were not horror - related at all.
Indeed, it is based on a real story. There were reports from the Lutz family who lived in the Amityville house. They described experiences such as doors slamming on their own, green slime oozing from the walls, and a feeling of being constantly watched. These strange happenings were then adapted into the movie 'The Amityville Horror 2005'. Whether one believes these events actually happened or not, they were the inspiration for the film.