1)A student conducts of the most popular colour of shirts for people to wear by recording the colour of every 25th person who entered the gate at the Toronto Blue Jays game.

a) What type of survey is this? Explain.

b) Does this survey contain any bias? Explain. 

2)A person is doing research on how many coffees a person has in one day. He/she decides to ask people questions as they enter the coffee shop.

a) What type of survey is this? Explain.

b) Does this survey contain any bias? Explain. 

1)

a) Systematic sampling. Systematic sampling selects people at a consistent interval from a population, as this does. This is not a random sample, however, because it is attempting to draw conclusions about a larger population from a a smaller, biased sample of people.

b) Yes, there is bias. Though systematic sampling can be nonbiased, it has to come from a random population. The population being sampled here is not random, as the colors people wear to a sports game frequently represent the teams playing, so results will be biased towards these colors. Therefore, this population is biased towards certain colors.

2)

a) Convenience sampling. A convenience sample is taken based on what's easiest and does not necessarily represent a random population, as is the case for this survey.

b) Yes, there is bias. You are not drawing results from a truly random population, yet are trying to draw conclusions for everyone. People who walk into a coffee shop are more likely to drink coffee and likely consume more coffee than the average person, which biases the results.