This is what a parameter is it should help you on the rest of the school year "The value of a parameter is a fixed number. In contrast to this, since a statistic depends upon a sample, the value of a statistic can vary from sample to sample. Suppose our population parameter has a value, unknown to us, of 10. One sample of size 50 has the corresponding statistic with value 9.5. Another sample of size 50 from the same population has the corresponding statistic with value 11.1." The only ones that fit this is b and d
