Who were the parents of Oscar Nysander Anderson?

The Anderson family was found on Ancestry World Tree.

What we knew
Birth date Oscar Nysander Anderson was born 7 Nov 1897 somewhere in North Dakota. 
Existing research According to the submitter, the 1930 census for Casper, Natrona, Wyoming contained this information:

Oscar N Anderson, 32. born in ND, parents born in MO
Agnis J Anderson, 25, born in MO, parents born in Norway
Larry B Anderson, 5, born in MO
Wayne R Anderson, 3, born in ND

Where we looked
1930 census
The first thing we did was look at the original page for the 1930 Wyoming census. By looking at the actual record, we discovered that Oscar's parents were born in Minnesota, not Missouri.
Military records
North Dakota Military Men, 1917-1918 is a collection of military records for men who served in the war from North Dakota. This database contained an entry for an Oscar Nysander Anderson born 7 Nov 1897 in Starkweather, ND.
1910 census
We used the 1910 head-of-household search at Ancestry.com to find Andersons in Ramsey county, ND. The index contains an Olaf P. N. Anderson, 38 years old, born in MN, and living in Starkweather.  

We used the roll and page information to review the actual record. 

What we learned
Parents The 1910 ND census record for Olaf P. N. Anderson included his wife Mina, 41 and several children including Oscar N. Anderson, age 12. Olaf and Mina were born in Minnesota, their parents were born in Norway, and their children were born in North Dakota.

Olaf's widowed mother-in-law, Keri Ingwaldson, 74, was also living with the family in 1910.

Grandparents We searched the 1880 census for Ingwaldsons born in Norway. In Traill county, Dakota Territory we found Carrie Ingwaldson, 44, and her husband Eric Ingwaldson, 50, both born in Norway. The family included several children, all born in Minnesota including Mary Ingwaldson, 11, who is most likely Oscar Anderson's mother Mina. 
Original records For this week's puzzle, we learned the value of looking at original records. Even after finding Oscar's birthplace, we might not have spotted the family in the index if we were looking for Andersons born in Missouri.

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