Final answer:
Issues of reliability when using existing statistics include sample representativeness, sample size, and measure reliability.
Step-by-step explanation:
When using existing statistics, there are several issues of reliability to consider. One issue is the representativeness of the sample. A sample needs to be representative of the population to avoid bias. Biased samples can lead to inaccurate and unreliable results.
Another issue is the size of the sample. Smaller samples may be unreliable, while larger samples are generally better. However, there are situations where small samples are necessary, such as in crash testing or medical testing for rare conditions.
Additionally, reliability refers to the consistency of a measure. A measure is reliable when it consistently produces the same results under the same circumstances. It is important to critically analyze statistical data to ensure its reliability.