Step 1

\(\displaystyle\overline{{{x}}}={11.6},\ {s}={4.3},\ {n}={200}\)

\(\displaystyle{s}_{{{x}}}={\frac{{{s}}}{{\sqrt{{{n}}}}}}={\frac{{{4.3}}}{{\sqrt{{{200}}}}}}={0.3041}\)

\(\displaystyle{n}={200}\)

\(\displaystyle{n}-{1}={199}\)

Step 2

\(\displaystyle{92}\%{C}.{I}.=\overline{{{x}}}\pm{T}{I}{N}{V}{\left({0.08},\ {199}\right)}{\left({s}_{{\overline{{{x}}}}}\right)}\)

\(\displaystyle={11.6}\pm{1.76}{\left({0.3041}\right)}\)

\(\displaystyle={11.6}\pm{0.54}\)

\(\displaystyle={\left({11.06},\ {12.14}\right)}\)

\(\displaystyle{T}{I}{N}{V}{\left(\alpha,\ {n}-{1}\right)}\) is a Excel function.