Thank you for the opportunity to help you with your question!

You will require a t-table or a details adding machine, since I am old fashioned I will utilize a t-table.

Since you have an example size of 26, you will have n - 1 degrees of opportunity, i.e., 26 - 1 = 25 degrees of flexibility.

Go to your t-table and search for the column that compares to 25 degrees of opportunity (The degrees of flexibility segment is typically down the left-hand side of the table, demonstrated by d.f. ).

When you have discovered the right line filter over the highest point of the table until you discover the segment that relates to 98% certainty.

Take after the 98% certainty section down until you meet the 11 degrees of opportunity line (Similar to how you read a guide).

For 98% certainty, your t-worth will be 2.718.

Please let me know if you need any clarification. I'm always happy to answer your questions.