Question: Identify the incorrect statement(s). I. Mean is the most stable measure of central tendency. II. If the mean of a set of 6 observations is 8 and the mean of a set of 4 observations is 9, then the mean for the combined set of observations is 8.4. III. To compare the heights of the students in a class, the most suitable measure of central tendency is Median. IV. Mode is the average suited for open ended classes.
A ) III and IV only B ) II, III and IV only C ) II and III only D ) all are incorrect
Steps to derive
1 The most stable measure of central tendency is mean.
2 8 is the mean of a set of 6 observations, 9 is the mean of a set of 4 observations. Mean of the combined set = (8×6)+(9×4)10 = 8.4
3 The difference in the heights of students of same class will not be much. So, mean is the best method to compare the heights of the students in a class.
4 Median is the average, suited for open ended classes.
