Answer:
mean = 80.5
standard deviation = 9.86
Given:
79, 88, 65, 90
To find the mean, we will use the following formula:

Where:
μ = mean
Σx = sum of all data points
N = number of data points
Using the given data, we know that:
Σx = 79+88+65+90
N = 4


Next, finding the standard deviation will be easier if we find the variance first. To find the variance, we will use the following formula:

And using the same data as earlier,

And then, to find the standard deviation, we are just going to get the square root of the variance
![\sigma=\sqrt[]{\sigma^2}](https://img.qammunity.org/2023/formulas/mathematics/college/1nil4daxtwmiiojjzy9q3k9t0m5jcp66vg.png)
![\sigma=\sqrt[]{97.25^{}}](https://img.qammunity.org/2023/formulas/mathematics/college/ib5y83yxfnn7dpxxi4olx8gh7m8zgz01yx.png)

Answer:
mean = 80.5
standard deviation = 9.86