Question

A video game company surveys a random sample of 225 of its best customer and finds that the average gamer spends $406 a year on games, with a standard deviation of $26. Another company is also interested in the amount game consumers spend, and surveys a random sample of 250 gamers, over all interest levels, and finds that the average gamer spends $250 a year on games, with a standard deviation of $15. Why is the second survey more believable than the first?

Answer 1

The second survey is more believable because there is randomness in the second rather than the first survey. Since the second company surveyed in all interest levels while the first company only surveyed their best customers. Random sampling like what the second company did helps produce representative samples by removing voluntary response bias and undercover age bias.