Consider two imaginary groups of five insured animals. In both groups, every cat policy costs $30 per month and every dog policy costs $60. The only change is how many of each animal appear in the group.
| Fictional group | Total monthly premiums | Average per animal |
|---|---|---|
| Four cats and one dog | 4 × $30 + 1 × $60 = $180 | $180 ÷ 5 = $36 |
| One cat and four dogs | 1 × $30 + 4 × $60 = $270 | $270 ÷ 5 = $54 |
The group average rises from $36 to $54 even though neither example price changed. This is an arithmetic demonstration of a mix effect, not NAPHIA data, a quote or an explanation of the actual market’s movement.
The same logical problem can arise within one species if the collection changes toward older animals, different breeds or broader products. A rising combined average alone cannot tell you how much any unchanged policy’s premium increased. You would need comparable detail to separate those influences.