Question

After you complete your survey of students reported heights at your school, you discover that your sample is biased. Exactly 10% of the students in your sample tended to over report their height more than the average student in the general population at the school. What conclusion can you reach about the mean of the average difference in your sample?

Answer 1

The mean of the reported heights at the school is 0.75 greater than the the mean of the actual measured heights at the school.

Answer 2

What we can say with a good deal of certainty is that our sample is biased towards the higher spectrum and that the real value of the mean for our population is lower than the obtained value of our sample. If this is true, we should expect for the standard deviation to be higher than in the population.