can Lambda value be considered as the time taken for average number of events in that time interval? as per the lecture Lambda is frequency of events in a specific time interval. So in that question - why is lambda not equal to avg events in time which is 2 (2 trees every four minutes).

Hey Sandesh, Thank you for reaching out! Note that it is important to consider the same time intervals. In the Q&A example in the lecture, the time interval was 1 day: Given that you receive 4 questions per day on average, what is the probability of receiving 7 questions today? Therefore, lambda = 4. In the practice exam question, we are told that the average number of trees per 4 minutes is 2. This makes for 4 trees per 8 minutes on average. Since the question asks for the probability of of less that 5 trees appearing in 8 minutes, we need to use lambda = 4. Hope this helps! Kind regards, 365 Hristina