A random selection of 1000 smartphone owners, ages 18-24 years old, were asked if they constantly check and use their phone. A total of 518 responded yes.
(a) Estimate the probability that, a smartphone owner in that age group constantly checks or uses his/her phone. Explain how you are using the long-run relative frequency interpretation of probability.
(b) If instead of a random sample, suppose the sample was restricted to communications science majors at a single large university. Comment on the estimate of probability for all smartphone owners in the 18-to-24-year-old age group.