Find the mean of 11, 15, 17, 6, and 21.

Answer

To find the mean of the numbers 11, 15, 17, 6, and 21, we will follow these steps:

### Step 1: Identify the numbers
The numbers given are:
- 11
- 15
- 17
- 6
- 21

### Step 2: Count the total number of observations
There are a total of 5 observations.

### Step 3: Calculate the sum of the observations
Now, we need to sum these numbers:
\[ 11 + 15 + 17 + 6 + 21 \]

Calculating step by step:
- First, add 11 and 15:
\[ 11 + 15 = 26 \]
- Next, add 17:
\[ 26 + 17 = 43 \]
- Then, add 6:
\[ 43 + 6 = 49 \]
- Finally, add 21:
\[ 49 + 21 = 70 \]

So, the sum of the observations is 70.

### Step 4: Divide the sum by the total number of observations
Now, we will divide the sum by the total number of observations to find the mean:
\[ \text{Mean} = \frac{\text{Sum of observations}}{\text{Total number of observations}} = \frac{70}{5} \]

Calculating this gives:
\[ \frac{70}{5} = 14 \]

### Step 5: State the mean
Thus, the mean of the numbers 11, 15, 17, 6, and 21 is:
\[ \text{Mean} = 14 \]

### Final Answer
The mean of the observations is **14**.

---