To find the standard deviation:
From the given table values,
Sum of the squared deviation is,
222.6064+166.9264+119.2464+98.4064+98.4064+79.5664+35.0464+8.5264+
3.6864+3.6864+0.8464+0.8464+0.0064+0.0064+0.0064+0.0064+4.3264+
4.3264+82.4464+82.4464+101.6064+145.9264+145.9264+145.9264+121.0864=1671.84.
The formula for standard deviation is,
Here, N=25
So we have,
Hence the standard deviation is,