I imagine she must have entered a wild card before 'hagger' so I tried it on the 1901 Census Online. I didn't get 'Schagger' but I did get three of my family members who had been mistranscribed and whom I assumed had been missed:
Crawford Mctehagga, 61, born Ireland, Balamina (sic), Parish: Bootle Cum Linacre, Lancs; Occupation: Labourer.
Elizabeth Mctehagger, 53, Born Ireland. Knockbride; Parish: Bootle Cum Linacre; and
John Mctehagga, 21, born Liverpool; Parish: Bootle Cum Linacre, Lancs; Clerk.
Crawford was my great-grandfather, and for the first time I have learned where my great-grandmother was born, Knockbride, which is in County Cavan, now in the Republic of Ireland. Thank you Australia!