Biased and Unbiased Point Estimates Practice Test

A school wants to estimate the population mean number of minutes students at the school spend on homework per night, $\mu$. A simple random sample of 60 students is selected, and each student reports their minutes. The point estimate is constructed as the sample mean, $\bar{x}$, computed by adding the 60 reported values and dividing by 60. Which statement describes whether the estimate is biased?

A wildlife biologist wants to estimate the population mean weight $\mu$ of adult fish in a lake. The biologist catches fish using a net with holes large enough that very small fish often escape before being weighed. The point estimate is the sample mean $\bar{x}$ of the weights of the 70 fish that are successfully caught and weighed. Which statement describes whether the estimate is biased?