Answer :
In this question, we're distinguishing between parameters and statistics, which are fundamental concepts in statistics.
Parameter: A parameter is a numerical value that summarizes or describes an aspect of a population. It is a fixed number, but in practice, we don’t know its true value unless we have data on the entire population.
Statistic: A statistic is a numerical value that summarizes or describes an aspect of a sample. It is used to make inferences about the parameter.
In the context of this question:
The mean annual temperature in Anchorage of 37 degrees Fahrenheit is described as being for the entire population of days in a typical year. Therefore, this value represents a parameter.
The measured mean temperature of 35.9 degrees Fahrenheit from a random sample of 65 days is a statistic, as it is derived from a sample and not the entire population.
This distinction is important because parameters are the actual characteristics of the population, while statistics are used to estimate those parameters. Understanding the difference helps when analyzing and interpreting statistical results.