Texas Instruments TI-83 PLUS - Manual (Page 409)

TI-83 Plus Inferential Statistics and Distributions 406
TInterval
TInterval (one-sample t confidence interval; item 8 ) computes a
confidence interval for an unknown population mean m when the
population standard deviation s is unknown. The computed confidence
interval depends on the user-specified confidence level.
In the example:
L 6 ={1.6 1.7 1.8 1.9}
Data Stats
Input:
, ,
Calculated results: