The problem in the image asks for the calculation of the standard deviation ("simpangan baku") and variance ("ragam") for the given dataset.

The dataset is:

$6, 8, 6, 7, 8, 7, 9, 7, 7, 7, 8, 6, 5, 8, 7$

Steps for Calculating the Variance and Standard Deviation:

1. Find the mean ($\mu$): $\mu = \frac{\sum x_i}{N}$ where $x_i$ are the data points and $N$ is the total number of data points.

2. Variance ($\sigma^2$): $\sigma^2 = \frac{\sum (x_i - \mu)^2}{N}$

3. Standard deviation ($\sigma$): $\sigma = \sqrt{\sigma^2}$

Let's calculate this step-by-step. I'll start with the mean.The mean ($\mu$) of the dataset is approximately $7.07$.

Next, I will calculate the variance ($\sigma^2$) and the standard deviation ($\sigma$).The variance ($\sigma^2$) of the dataset is approximately $0.996$, and the standard deviation ($\sigma$) is approximately $0.998$.

Would you like more details on how these calculations were done or have any questions?

Here are 5 related questions:

1. How do we interpret the variance in a dataset?
2. What is the significance of the standard deviation in statistics?
3. How does standard deviation affect data spread?
4. What is the difference between population and sample variance?
5. How would the standard deviation change if outliers were added to the dataset?

Tip: Variance helps in understanding the spread of the data, but standard deviation is often preferred for interpretation since it's in the same units as the data.