# Python statistics.mean() Function

Python statistics.mean() method is used to calculate the mean/average of a given list of numbers.

To use the mean() method, you need to import the statistics module.

## Syntax

``````mean(data)
``````

## Parameters

data: List or tuple of a set of numbers.

## Return value

It is a sample arithmetic mean of the provided data set.

## Exceptions

TypeError occurs when anything other than numeric values is passed as a parameter.

## Example 1: Calculating the mean of a list

``````import statistics

main_list = [1, 1, 2, 2, 3]

mean_of_list = statistics.mean(main_list)

print(mean_of_list)``````

Output

``````1.8
``````

## Example 2: Calculating the mean of the dictionary

``````import statistics

main_dict = {1: 19, 1:21, 2:18, 2:46, 3:30}

mean_of_dict = statistics.mean(main_dict)

print(mean_of_dict)
``````

Output

``2``

## Example 3: Calculating a mean of a tuple of a negative set of integers

``````import statistics

negative_set = (-11, -21, -18, -19, -46)

mean_of_negative_set = statistics.mean(negative_set)

print(mean_of_negative_set)
``````

Output

``-23 ``

Let’s take an example of the tuple of a mixed range of numbers.

``````import statistics

mixed_set = (11, 21, -18, 19, -46)

print(statistics.mean(mixed_set))``````

Output

``-2.6``

## Example 4: Calculating the mean of a list of a negative set of integers

``````import statistics

negative_list = [-11, -21, -18, -19, -46]

mean_of_negative_list = statistics.mean(negative_list)

print(mean_of_negative_list)
``````

Output

``-23``

Let’s take an example of the list of a mixed range of numbers.

``````import statistics

mixed_list = [11, 21, -18, -19, 46]

print(statistics.mean(mixed_list))``````

Output

``8.2``

## Example 5: TypeError: can’t convert type ‘str’ to numerator/denominator

``````import statistics

data = {"a": 11, "b": 21, "c": 19, "d": 29, "e": 18}

print(statistics.mean(data))``````

Output

``TypeError: can't convert type 'str' to numerator/denominator``

We got the TypeError because statistics.mean() expects an iterable of numbers, and we passed an entire dictionary data instead of just its values.

The correct approach is to extract the values from the dictionary using dict.values() function and then calculate the mean.

``````import statistics

data = {"a": 11, "b": 21, "c": 19, "d": 29, "e": 18}

# Extract the values from the dictionary and calculate the mean
mean_value = statistics.mean(data.values())

print(mean_value)
``````

Output

``19.6``

That’s all!

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