Question

For parts a and b​, use technology to estimate the following. ​a) The critical value of t for a 98 ​% confidence interval with dfequals 9 . ​b) The critical value of t for a 90 ​% confidence interval with dfequals 111 . ​a) What is the critical value of t for a 98 ​% confidence interval with df equals 9​?

Answer 1

df	confidence level	t critical value	excel function
a).9	98% = 0.98 alpha = (1-0.98) = 0.02	2.821	in any blank cell of excel type =T.INV.2T(0.02,9) press enter.
b).111	90% = 0.90 alpha = (1-0.90) = 0.10	1.659	in any blank cell of excel type =T.INV.2T(0.1,111) press enter.

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