Resolved: Excel formula to find number in the Z-table
HI,
I'm struggling to find an automated way to lookup the number in th Z-table. Refer to 5:10, I finally managed to do this by formula, but this doesn't work for CI 90% or 95% (refer to 6:30)
Here's what I've done so far:
- F38 is number to lookup (0.9750 in this case)
- ZTABLE is the the named range of the z-table in a separated sheet
Get Z-Table column ---> Result: 0.06
=INDEX(ZTABLE,1,SMALL(IF(NOT(ISERROR(SEARCH(F38,ZTABLE))),COLUMN('Z-Table'!A:K),99^99),1))
Get Z-Table row ---> Result: 1.90
=INDEX(ZTABLE,SMALL(IF(NOT(ISERROR(SEARCH(F38,ZTABLE))),ROW('Z-Table'!1:36),99^99),1),1)
Zα /2 = Z-Table column + Z-Table row (1.96)
Is there any simpler way finding Zα /2 that can be solved by formula instead of manually find the number in the table?
Thanks
3 answers ( 1 marked as helpful)
Super learner
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You can try the NORMSINV function in excel.
Thanks Eugene! This make more sense than looking up the table.
=NORMSINV(probability)=NORMSINV(0.95) or you can also use the excel function Z.INV(probability, mean, standard_deviation)
=Z.INV(probability, mean, standard_deviation)=Z.INV(0.95,0,1)