No, stereotyping would apply some assumptions to an individual based on his group. This on the other hand is a plausible statistical claim.

Some stereotypes are based on loud minorities, but others manifest due to the it being true on a statistically meaningful scale. I think it is safe to say on average Japanese have more seaweed in their diet. So if I met a random Japanese person and assume they eat seaweed, then I am stereotyping, but it is rational and informed stereotyping, nothing rude about it.