Let's compile the numbers and perform the requested calculations step by step:

Numbers Given:

14, 17, 30, 12, 17, 17, 15

Step 1: Sorting the Numbers

Sorted order: 12, 14, 15, 17, 17, 17, 30

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Step 2: Calculating the Median

• Median: The middle value of the sorted list.
• Since there are 7 numbers, the median is the 4th number: 17.

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Step 3: Calculating the Average

1. Sum of the Numbers:
   $12 + 14 + 15 + 17 + 17 + 17 + 30 = 122$

2. Count of Numbers: 7.

3. Raw Average:
   $\text{Average} = \frac{\text{Sum}}{\text{Count}} = \frac{122}{7} \approx 17.43$

4. Rounding the Average (per the rules):

   • $17.43$ is rounded down to 17 since it is above 11 but less than 19.

5. Ensuring the Boundaries:
   The rounded average (17) is within the bounds (does not exceed 21), so no adjustment is needed.

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Final Results:

• Median: 17.
• Average: 17.

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Let me know if you'd like additional details or have further questions. Here are five related questions for exploration:

1. How do you calculate the mode of a dataset?
2. What is the difference between mean, median, and mode?
3. How do outliers like 30 affect the average of a dataset?
4. What is the impact of rounding rules on statistical analysis?
5. How would the results change if the rounding rules were different?

Tip: When calculating the average, always confirm the range of numbers beforehand to anticipate the influence of extreme values.