For each of the scenarios below, determine if the sample is a simple random sample from the population of interest, or if the sample has some form of bias. If there is a bias, describe the nature of the bias in a sentence or two.

(a) You are interested in the average height of all freshmen on the UW-Madison campus. You draw a simple random sample of freshmen in your statistics class.
(b) You are interested in the rage of the glaze thicknesses on mugs created in a factory. Yon sample every 5th mug off of the assembly line.
(c) You are interested in the average IQ of 6th graders in Dane County public schools. You get your sample by using computer software to randomly select 100 6th grade student ID numbers from the Dane County public school database.
(d) You work for a doctor's office and you are interested in estimating the proportion of patients that visited the office n the last month that feel they received satisfactory care. You randomly select names from the list of patients who have been to the office and email them a survey. About 25% of the surveys are returned.