1. What happens if there is more than one mode for a set of value?
For the set of values 3, 4, 4, 5, 6, 7, 7, 8 there are two modes, 4 and 7. Give them both. The set of values is said to be bi-modal.
2. What is the disadvantage of using the median as an average for a set of scores?
It does not give any indication of any extremely small or large values in the set.
e.g. The median of 4, 5, 6, 7, 100 is 6 but this does not give any indication of the very high value of 100. The mean would include the value of 100 in its calculation.
3. What is the disadvantage of using the mean as an average for a set of scores?
One really large or small value can have a big effect on the mean. In the example above the mean will be much higher because of the effect of the value of 100.
4. What is the disadvantage of using the mode as an average for a set of scores?
The mode may not be typical of the whole set of values. Could be a long way from the middle values of the set.
e.g. 3, 3, 12, 13, 14, 15 15, 16. The mode is 3 but is not typical of the set of values.
5. Which of the three averages mean, median and mode do people usually use?
The mean is probably what most people would normally call the "average".