Given Four Observed Values $x _ { 1 } = 4.6 , x _ { 2 } = 6.2 , x _ { 3 } = 3.7 \text {, and } x _ { 4 } = 5.5 \text {, }$

Given four observed values: $x _ { 1 } = 4.6 , x _ { 2 } = 6.2 , x _ { 3 } = 3.7 \text {, and } x _ { 4 } = 5.5 \text {, }$ would result in a point estimate for $\mu$ that is equal to __________.