The tvalue for a tdistribution with 1 degree of freedom is 1

The t-value for a t-distribution with 1 degree of freedom is 1.28. What is the area/probability to the LEFT of 1.28?Please explain how you got to this answer!

Solution

df=1, and t value is 1.28. From t-table one-tailed probability for df=1, the t-value 1.28 is between 1.000 (corresponding to one tailed probability 0.25) and 1.376 (corresponding to one tailed probability 0.20). So the area  to the LEFT of 1.28 is between 0.28 and 0.20. From calculator the exact area is 0.2111