Use invT or invNorm together with technology or the t-table to find $t_{0.025}$ if $d f=13$. Round your answer to 3 decimal places.

Step 1 ：The problem is asking for the t-value for a two-tailed test with a significance level of 0.05 (because 0.025 is half of 0.05) and degrees of freedom (df) of 13. This is a statistics problem and can be solved using the inverse cumulative distribution function (CDF) for the t-distribution, also known as the t-inverse function. The t-inverse function gives the t-value below which a given percentage of the distribution lies.

Step 2 ：We have degrees of freedom (df) as 13 and significance level (alpha) as 0.025.

Step 3 ：Using the inverse cumulative distribution function for the t-distribution, we find the t-value to be approximately 2.1603686564610127.

Step 4 ：Rounding this to three decimal places, we get \(2.160\).

Step 5 ：Final Answer: The t-value for a two-tailed test with a significance level of 0.05 and degrees of freedom of 13 is approximately \(\boxed{2.160}\).