C# Online Compiler | .NET Fiddle

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    public static void Main()
    {
        List<Post> posts = new List<Post>
        {
            new Post { PostID = 1, UserID = 1, Timestamp = new DateTime(2023, 3, 10), ContentLength = 120, EngagementCount = 15 },
            new Post { PostID = 2, UserID = 1, Timestamp = new DateTime(2023, 3, 11), ContentLength = 300, EngagementCount = 25 },
            new Post { PostID = 3, UserID = 2, Timestamp = new DateTime(2023, 3, 12), ContentLength = 150, EngagementCount = 5 },
            new Post { PostID = 4, UserID = 2, Timestamp = new DateTime(2023, 3, 13), ContentLength = 200, EngagementCount = 8 },
            new Post { PostID = 5, UserID = 1, Timestamp = new DateTime(2023, 3, 14), ContentLength = 500, EngagementCount = 30 },
            // Add more post entries as needed
        };

        // Step 1: Calculate the average content length and total engagement count for each user
        var userStats = posts
            .GroupBy(p => p.UserID)
            .Select(g => new
            {
                UserID = g.Key,
                AverageContentLength = g.Average(p => p.ContentLength),
                TotalEngagementCount = g.Sum(p => p.EngagementCount)
            })
            .ToList();

        // Step 2: Identify the user with the highest total engagement count
        var topUser = userStats
            .OrderByDescending(u => u.TotalEngagementCount)
            .First();

        Console.WriteLine($"User with Highest Total Engagement: UserID {topUser.UserID}, Total Engagement: {topUser.TotalEngagementCount}");

        // Step 3: Analyze the correlation between content length and engagement count for the top user
        var topUserPosts = posts
            .Where(p => p.UserID == topUser.UserID)
            .Select(p => new { p.ContentLength, p.EngagementCount })
            .ToList();

        // Simple correlation analysis
        var longerPosts = topUserPosts.Where(p => p.ContentLength > topUserPosts.Average(p => p.ContentLength)).ToList();
        var higherEngagement = longerPosts.Average(p => p.EngagementCount) > topUserPosts.Average(p => p.EngagementCount) ? "Yes" : "No";

        Console.WriteLine($"Do Longer Posts Receive More Engagement for Top User? {higherEngagement}");
    }
}

public class Post
{
    public int PostID { get; set; }
    public int UserID { get; set; }
    public DateTime Timestamp { get; set; }
    public int ContentLength { get; set; }
    public int EngagementCount { get; set; }
}

 
using System;
using System.Collections.Generic;
using System.Linq;
​
public class Program
{
    public static void Main()
    {
        List<Post> posts = new List<Post>
        {
            new Post { PostID = 1, UserID = 1, Timestamp = new DateTime(2023, 3, 10), ContentLength = 120, EngagementCount = 15 },
            new Post { PostID = 2, UserID = 1, Timestamp = new DateTime(2023, 3, 11), ContentLength = 300, EngagementCount = 25 },
            new Post { PostID = 3, UserID = 2, Timestamp = new DateTime(2023, 3, 12), ContentLength = 150, EngagementCount = 5 },
            new Post { PostID = 4, UserID = 2, Timestamp = new DateTime(2023, 3, 13), ContentLength = 200, EngagementCount = 8 },
            new Post { PostID = 5, UserID = 1, Timestamp = new DateTime(2023, 3, 14), ContentLength = 500, EngagementCount = 30 },
            // Add more post entries as needed
        };
​
        // Step 1: Calculate the average content length and total engagement count for each user
        var userStats = posts
            .GroupBy(p => p.UserID)
            .Select(g => new
            {
                UserID = g.Key,

Roslyn 2.0 Compiler; Environment version: 4.0.30319.42000

John Smith
John Smith