Given data
*The given mean is u = 2.3 pounds
*The total number of macaw parts is n = 38
*The given standard deviation is Q = 0.20 Pounds
Z-score for 90% confidence interval is Z = 1.645
The formula for the confidence interval is given as
[tex]s=u\pm\frac{zQ}{\sqrt[]{n}}[/tex]Substitute the values in the above expression as
[tex]\begin{gathered} s=2.3\pm\frac{1.645\times0.20}{\sqrt[]{38}} \\ =2.3\pm0.05337 \\ =2.24,2.35\text{ pounds} \end{gathered}[/tex]