1. **State the problem:** We are given a data set and asked to check the calculations of mean, median, range, variance, and standard deviation.
2. **Mean calculation:** The mean $\bar{X}$ is the sum of all data points divided by the number of points.
$$\bar{X} = \frac{175 + 190 + 250 + 230 + 240 + 200 + 185 + 190 + 225 + 265}{10} = \frac{2150}{10} = 215$$
This matches the given mean.
3. **Median calculation:** The median is the middle value when data is ordered. The ordered data is:
$$175, 185, 190, 190, 200, 225, 230, 240, 250, 265$$
Since there are 10 values (even), median is average of 5th and 6th values:
$$m = \frac{200 + 225}{2} = \frac{425}{2} = 212.5$$
The user wrote $222.5$ which is incorrect; correct median is $212.5$.
4. **Range calculation:** Range is max minus min:
$$265 - 175 = 90$$
This matches the given range.
5. **Variance calculation:** Variance formula for sample variance is:
$$s^2 = \frac{\sum (x_i - \bar{X})^2}{n-1}$$
Calculate each squared difference:
$$(175-215)^2 = 1600$$
$$(185-215)^2 = 900$$
$$(190-215)^2 = 625$$
$$(190-215)^2 = 625$$
$$(200-215)^2 = 225$$
$$(225-215)^2 = 100$$
$$(230-215)^2 = 225$$
$$(240-215)^2 = 625$$
$$(250-215)^2 = 1225$$
$$(265-215)^2 = 2500$$
Sum these:
$$1600 + 900 + 625 + 625 + 225 + 100 + 225 + 625 + 1225 + 2500 = 8650$$
Divide by $n-1=9$:
$$s^2 = \frac{8650}{9} = 961.11$$
This matches the given variance.
6. **Standard deviation calculation:** Standard deviation is square root of variance:
$$s = \sqrt{961.11} = 31.00$$
This matches the given standard deviation.
**Summary:** Mean, range, variance, and standard deviation calculations are correct.
Median calculation is incorrect; correct median is $212.5$ not $222.5$.
Data Statistics 36Ed14
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.