[Cryptic™]

Could someone show me how to do one of them?

[pdiddy413]

To do this, you need either a T-chart or a graphing calculator (at least TI-83). I'll explain how to do both. First, you will need to know your degrees of freedom, which is n-1. Next, since you are performing an upper tail test, the two tails together is alpha, so the upper tail is alpha/2, but the table and calculator use the number 1-alpha/2.
Using the first example: 1-alph=.9, so alpha = .1, and alpha/2 is .05, so the number needed is 1-.05=.95.
For degrees of freedom, n-1 = 31-1 = 30.
If you have a t-chart (located in the back of your stats book), df (sometimes labeled v) is usually the left column, and 1-alph/2 is the top row. So if you intersect 30 & .95, you get 1.697.
If you have a TI-83-84, use 2nd VARS 4 (InvT). If it gives the prompts: area & df, enter .95 and 30 respectively.
If it just opens up parenthesis then type (.95, 30) (separated by a comma) then enter. Your result should be: 1.697260851.
I hope this helps.

[Cryptic™]

To do this, you need either a T-chart or a graphing calculator (at least TI-83). I'll explain how to do both. First, you will need to know your degrees of freedom, which is n-1. Next, since you are performing an upper tail test, the two tails together is alpha, so the upper tail is alpha/2, but the table and calculator use the number 1-alpha/2.
Using the first example: 1-alph=.9, so alpha = .1, and alpha/2 is .05, so the number needed is 1-.05=.95.
For degrees of freedom, n-1 = 31-1 = 30.
If you have a t-chart (located in the back of your stats book), df (sometimes labeled v) is usually the left column, and 1-alph/2 is the top row. So if you intersect 30 & .95, you get 1.697.
If you have a TI-83-84, use 2nd VARS 4 (InvT). If it gives the prompts: area & df, enter .95 and 30 respectively.
If it just opens up parenthesis then type (.95, 30) (separated by a comma) then enter. Your result should be: 1.697260851.
I hope this helps.

Got it. Thank you!