Final answer:
The percentage (39.5%) of California residents who speak a language other than English at home, according to the 2000 census, is a statistic because it describes a sample of California's population at that time.
Step-by-step explanation:
Based on the 2000 census, the percentage (39.5%) of California residents who speak languages other than English at home is a statistic. A statistic is a measurement that describes a sample, which in this context is a subset of California's population at the time of the 2000 census. Parameters, on the other hand, describe an entire population. The term 'variable' refers to a characteristic that can vary and a 'constant' is a value that does not change.
In terms of conducting a study, if you were to examine the entire population of interest, your measurement would be referred to as a parameter. However, when a proportion is derived from a sample, such as the figure given from the census or a class in a school, it is considered a statistic.