they often do not represent an accurate cross section of the total population.
Straw vote polling is highly unreliable because nothing in the process ensures that those who respond will represent a reasonably accurate cross section of the total population.
they are unreliable because there old.
You are studying the sample because you want to find out information about the whole population. If the sample you have drawn from the population does not represent the population, you will find out about the sample but will not find out about the population.
The device tended to jam and malfunction because the parts of the machine were unreliable.
The device tended to jam and malfunction because the parts of the machine were unreliable.
Jo did not trust her friend because she heard rumours about her being unreliable.
Varies from country to country, and statistics are unreliable, because some people do not admit drug-taking, others claim it for bravado, but do not do it.
because they where after the event
personal pages are unreliable because anyone can change anything on the page of the specified website.
Unreliable
Of course they do. Population wise not really, because population doesn't decide the election. Only the electoral collage does. The blue states represent Decorates and the red states represent Republicans.