```ts
export function fieldMean(records: Record<string, number>[], field: string): number {
  if (records.length === 0) return 0;

  let sum = 0;
  let count = 0;

  for (const record of records) {
    if (record.hasOwnProperty(field)) {
      const value = record[field];
      if (typeof value !== 'number') continue; // Skip non-numeric values

      sum += value;
      count++;
    }
  }

  return Math.floor(sum / count);
}
```