1. **Problem:** Find the mean and standard deviation of the annual salaries: 85, 75, 77, 79, 80, 78, 82, 78, 73, 64 (in thousands).
2. **Formula:**
- Mean: $$\bar{x} = \frac{1}{n} \sum_{i=1}^n x_i$$
- Standard deviation: $$s = \sqrt{\frac{1}{n-1} \sum_{i=1}^n (x_i - \bar{x})^2}$$
3. **Calculate the mean:**
$$\bar{x} = \frac{85 + 75 + 77 + 79 + 80 + 78 + 82 + 78 + 73 + 64}{10} = \frac{771}{10} = 77.1$$
4. **Calculate each squared deviation:**
$$(85 - 77.1)^2 = 62.41$$
$$(75 - 77.1)^2 = 4.41$$
$$(77 - 77.1)^2 = 0.01$$
$$(79 - 77.1)^2 = 3.61$$
$$(80 - 77.1)^2 = 8.41$$
$$(78 - 77.1)^2 = 0.81$$
$$(82 - 77.1)^2 = 24.01$$
$$(78 - 77.1)^2 = 0.81$$
$$(73 - 77.1)^2 = 16.81$$
$$(64 - 77.1)^2 = 171.61$$
5. **Sum of squared deviations:**
$$62.41 + 4.41 + 0.01 + 3.61 + 8.41 + 0.81 + 24.01 + 0.81 + 16.81 + 171.61 = 292.9$$
6. **Calculate standard deviation:**
$$s = \sqrt{\frac{292.9}{10 - 1}} = \sqrt{\frac{292.9}{9}} = \sqrt{32.544} = 5.705$$
**Final answer:** Mean = 77.1, Standard deviation = 5.705
This corresponds to option (B).
Mean Standard Deviation 3D0A53
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