Question

Using a graphing calculator find the value of tα/2 for a 90% confidence interval when the sample size is 6.

Answer 1

We will calculate the alpha level

`\begin{gathered} \alpha=1-confidence\text{ interval} \\ \end{gathered}`

The confidence interval given is

`C\mathrm{}I=90\text{ \%=0.90}`

Therefore, the alpha value will be

`\begin{gathered} \alpha=1-0.90 \\ \alpha=0.10 \end{gathered}`

Therefore,aplha/2 will be

`\begin{gathered} (\alpha)/(2)=(0.10)/(2) \\ (\alpha)/(2)=0.05 \end{gathered}`

Let's calculate the degree of freedom(df)

`\begin{gathered} df=n-2 \\ \text{where n=sample size=6} \\ df=6-2 \\ df=4 \end{gathered}`

Using the graphing calculator, t(alpha/2) will =2.131802