给定一个由整数组成的数组，使用Python编写函数来计算数组的平均值、中位数和众数。
[2, 3, 4, 4, 5, 6, 7, 7, 7, 8, 8, 9, 9, 9, 9, 10]
计算平均值：

```python
def get_mean(arr):
    return sum(arr) / len(arr)
    
arr = [2, 3, 4, 4, 5, 6, 7, 7, 7, 8, 8, 9, 9, 9, 9, 10]
mean = get_mean(arr)
print(mean) # 6.4375
```

计算中位数：

```python
def get_median(arr):
    sorted_arr = sorted(arr)
    n = len(arr)
    mid = n // 2 
    if n % 2 == 0:
        return (sorted_arr[mid - 1] + sorted_arr[mid]) / 2
    else:
        return sorted_arr[mid]

arr = [2, 3, 4, 4, 5, 6, 7, 7, 7, 8, 8, 9, 9, 9, 9, 10]
median = get_median(arr)
print(median) # 7.0
```

计算众数：

```python
def get_mode(arr):
    freq_dict = {}
    for num in arr:
        if num in freq_dict:
            freq_dict[num] += 1
        else:
            freq_dict[num] = 1
    
    mode_list = []
    for k, v in freq_dict.items():
        if v == max(freq_dict.values()):
            mode_list.append(k)
    
    return mode_list

arr = [2, 3, 4, 4, 5, 6, 7, 7, 7, 8, 8, 9, 9, 9, 9, 10]
mode = get_mode(arr)
print(mode) # [9]
```

因此数组的平均值为6.4375，中位数为7.0，众数为9。