A period is a temporal differential between the same event. The watch ticks once a second, the Earth rotates around the Sun once every 365.24 days.
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Firstly, it means "The Average". The mean is when you add all of the numbers together, then divide by how many numbers there are.
This happened to my friend's mum and she had to go to hospital and she nearly died !!! omg maybe go to the doctors
The mean is the sum of all elements in the sequence divided by the total number of elements. It is a statistic which represents the expected value of any term in the sequence (the average value).