I am in confusion that why 1,2,5 are true why not 1,2,4. can any one help me with explanation?

I am in confusion that why 1,2,5 are true why not 1,2,4. can any one help me with explanation?

1)Sample mean is always same as population mean.

2). One large sample collected from the population had the mean A and one small sample collected from the same population had the mean B, A is always closer to the population mean compared with B.

3). Sample statistics can be used to estimate population means and population standard deviations.

4). Sample statistics can be used to estimate population means but not to estimate population standard deviations.

5). Sample standard deviation is always same as population standard deviation.