We know:
[tex]\begin{gathered} \bar{x}=2.35 \\ S=1.1 \\ n=40 \\ \mu=2.3 \end{gathered}[/tex]The probability is:
[tex]t=\frac{\bar{x}-\mu}{\frac{s}{\sqrt{n}}}=\frac{2.3-2.35}{\frac{1.1}{\sqrt{40}}}=0.2875[/tex]Then, from the normal distribution table:
[tex]\begin{gathered} 0.28\rightarrow0.6103 \\ 0.29\rightarrow0.6141 \end{gathered}[/tex]Now we compute the values in the calculator for the obtained value:
[tex]0.2875\rightarrow0.613[/tex]The probability is 0.613.