IGI Individual Record FamilySearch™ International Genealogical Index v5.0 British Isles
JOSEPH SEDMAN Christening:  12 APR 1789 Scalby Near Scarborough, Yorkshire, England Parents: Father: JOHN SEDMAN Mother: ELIZABETH  
Source Information:Batch No.:  C106412 Dates: 1730 - 1812 Source Call No.: 0919204 Type:  Film Printout Call No.:  6910826

There are a Ellen aged 8 and William aged 2 living with the family on the 1841 census for Burniston.  I have no idea who these children are.

1841 England Census Record info about Joseph Sedman
Name: Joseph Sedman Age: 50 Estimated birth year: abt 1791 Gender: Male Where born: Yorkshire, England Civil parish: Scalby Hundred: Pickering Lythe County/Island: Yorkshire Source information: HO107/1261/7 Registration district: Scarborough Sub-registration district: Scarborough ED, institution, or vessel: 1 Folio: 7 Page: 6 Line number: 20 GSU Number: 464235
Ellen Sedman abt 1833 Yorkshire, England Scalby  Yorkshire  
Hannah Sedman abt 1791 Yorkshire, England Scalby Yorkshire 
Hannah Sedman abt 1829 Yorkshire, England Scalby Yorkshire 
Hodgson Sedman abt 1821 Yorkshire, England Scalby Yorkshire 
Joseph Sedman abt 1791 Yorkshire, England Scalby Yorkshire

Ellen Sedman is 17 and still living with the family in the 1851 census as well as a Mary E. Coats, visitor who is 1 and a shoe maker's daughter born Scarborough and a William Dedman, grand son, aged 12 born Burniston.

1851 England Census Record info about Joseph Sedman
Name: Joseph Sedman Age: 60 Estimated birth year: abt 1791 Relation: Head Gender: Male Where born:Burniston, Yorkshire, England Civil parish: Burniston County/Island: Yorkshire Country: England 
Source information: HO107/2368 Registration district: Scarborough Sub-registration district: Filey ED, institution, or vessel: 6 Folio: 574 Page: 5 Household schedule number: 25 GSU Number: 87646-87649
Mary E Coates abt 1850 Scarborough, Yorkshire, England Visitor Burniston Yorkshire  
Ellen Sedman abt 1834 Burniston, Yorkshire, England Daughter Burniston Yorkshire 
Hannah Sedman abt 1791 Burniston, Yorkshire, England Wife Burniston Yorkshire 
Joseph Sedman abt 1791 Burniston, Yorkshire, England Head Burniston Yorkshire 
William Sedman abt 1839 Burniston, Yorkshire, England Grandson Burniston Yorkshire

1861 England Census Record info about Joseph Sedman
Name: Joseph Sedman Age: 75 Estimated birth year: abt 1786 Relation: Head Gender: Male Where born: Burniston, Yorkshire, England Civil parish: Burniston County/Island: Yorkshire Source information: RG9/3620 Registration district: Scarborough Sub-registration district: Scarborough ED, institution, or vessel: 25 Folio: 64 Page: 10 Household schedule number: 68 GSU Number: 543162
Hannah Sedman  abt 1786 Burniston, Yorkshire, England Wife Burniston Yorkshire  
John Sedman abt 1854 Burniston, Yorkshire, England Grandson Burniston Yorkshire 
Joseph Sedman abt 1786 Burniston, Yorkshire, England Head Burniston Yorkshire

England & Wales, FreeBMD Death Index: 1837-1983 Record about Joseph Sedman
Name: Joseph Sedman Year of Registration: 1862 Quarter of Registration: Jan-Feb-Mar District: Scarborough County: East Riding Of Yorkshire, North Riding Of Yorkshire Volume: 9d Page: 208