Answer:
[tex]a)~s\\b)~\sigma\\c)~s^2\\d)~\sigma^2[/tex]
Step-by-step explanation:
We have to write the symbols for the following
(a) sample standard deviation
The sample standard deviation is represented by symbol "s"
(b) population standard deviation
The population standard deviation is represented by symbol "[tex]\sigma[/tex]"
(c) sample variance
The sample variance is represented by symbol "[tex]s^2[/tex]"
(d) population variance
The population variance is represented by symbol "[tex]\sigma^2[/tex]"