Question

state whether the following results are not reliable and valid. explain.

a national politics survey asks a group of high school students what party they favour in order to determine which party will win the next election.
b. all the traffic lights in a town are times and it is found that they consistently stay yellow for four hours.
c.the radio station fan 590 has a phone-in-survey to determine if the coach of the Toronto Maple Leafs should be fire and 93% of the people who call in are in favour.

Answer 1

a. Invalid. Here, the error that occurs is known as the Sample Frame Error, where the wrong subpopulation is used to select the sample. Here, high school students are presumably below the voting age, so to ask which party they favour would be useless as they will not be able to vote . Hence, high school students are a wrong subpopulation to choose for an election survey.

b. Valid. Since, in this survey, the whole population of traffic lights in the town are selected, the result that they consistently stay yellow for four hours should be valid for that town.

c. Invalid. Here, the error that occurs is known as the Selection Error, where the respondents select their own participation in the study, thus those who are interested only respond. Here, a phone in survey was done where people were are to call in to determine if the coach of the Toronto Maple Leafs should be fired. Thus, it is more than likely that those who are more interested to get the coach fired called in to respond more. Hence, the population wasn't equally represented .