1) Two different samples of size 100 each were randomly picked from a population of 10000 people. For each of the samples, the 95% confidence interval for the average height of the population was calculated. What can be said about the average population height, with respect to the two confidence intervals?

a) It must not lie in any of these confidence intervals.

b) It may or may not lie in any of these confidence intervals.

c) It must lie in exactly one of these confidence intervals.

d) It must lie in both of these confidence intervals.

2) To find out the average Mathematic final exam mark last semester, the final exam marks of all Mathematic students from last semester were gathered. An average from this data was calculated. Assuming that no data was lost in the process, which of the following can cause this average to differ from the true average?

1) Random Error

2) Non response bias

3) Selection Bias

4) None of the above