Naming Practices

I've found that in my searches that the Norwegians most often use the "E" in the patronymic names, such as Olsen, Olessen, Johansen etc and the Swedish used the "O" Olson, Olafson. And for daughters in Norway was datter and Sweden was dotter at least before becoming Americanized. This is what I have seen in my limited findings but is this true naming practices? Or have I just seen an individuals writing practice?