Question 1170783
To find the margin of error (E), we'll use the following formula:

E = z_c * (σ / √n)

Where:

* E = margin of error
* z_c = the critical z-value corresponding to the confidence level (c)
* σ = the population standard deviation
* n = the sample size

**1. Find the Critical z-Value (z_c)**

* c = 0.95 (95% confidence level)
* For a 95% confidence level, the critical z-value (z_c) is approximately 1.96. You can find this value using a z-table or a calculator.

**2. Plug in the Values**

* z_c = 1.96
* σ = 3.1
* n = 64

E = 1.96 * (3.1 / √64)

**3. Calculate the Margin of Error**

* √64 = 8
* E = 1.96 * (3.1 / 8)
* E = 1.96 * 0.3875
* E = 0.76

**Answer:**

E = 0.760 (rounded to three decimal places)