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## How to calculate mean in python?

Mean, also known as average is the sum of all the terms divided by a number of terms. In other words, it is the average of all the numbers.

Mean can be calculated using a loop, using sum() and len() functions, or by importing statistics module.

### Calculating mean using sum() and len() functions

sum() and len() are inbuilt functions in python to calculate the sum and number of elements of a numeric data set respectively.

Consider a list num_list = [5, 3, 2, 8, 9, 1]. The value returned by sum() function is stored in a variable add and the value returned by function len() is stored in variable num_terms.

The variable add is divided by num_terms to get the mean value.

``````num_list = [5, 3, 2, 8, 9, 1]
num_terms = len(num_list)
print("The mean of all the terms is: ", mean )``````

Output

``The mean of all the terms is:  4.666666666666667``

### Calculating mean by importing statistics module

Python supports a built-in module known as statistics, to calculate statistics of numeric data. statistics.mean() can be used to calculate the mean of numbers in a data set. The statistics module can be used with data set like lists, tuple, or sets.

``````import statistics
num_set = {5, 3, 2, 8, 9, 1}
avg = statistics.mean(num_set)
print("The mean of all the terms is: ", avg)
``````

Output

``The mean of all the terms is:  4.666666666666667``

### Calculating mean using for loop

Let us consider num_list = [5, 3, 2, 8, 9, 1]. A variable num_terms is initialized to '0', to count the number of terms. A for loop is used to iterate over the list num_list. After encountering every element the value is added to the variable add and num_terms is incremented by 1. The variable add is divided by num_terms to get the mean value.

``````num_list = [5, 3, 2, 8, 9, 1]
num_terms = 0
for i in num_list:
num_terms += 1
print("The mean of all the terms is: ", mean )
``````

Output

``The mean of all the terms is:  4.666666666666667``

### Calculating mean by importing statistics module

Python supports a built-in module known as statistics, to calculate statistics of numeric data. statistics.mean() can be used to calculate the mean of numbers in a data set. The statistics module can be used with data set like lists, tuple, or sets.

``````import statistics
num = {5,3,2,8,9,1}
avg = statistics.mean(num)
print("The mean of all the terms is: ",avg)
``````

Output

``The mean of all the terms is:  4.666666666666667``
If anything other than numeric values is present in the sequence as a TypeError Exception is raised.

For example,

``````num_list = [5, 3, 2, 8, 9, 1, "Hello"]
`````` add = sum(num)