1What is another name for quartile deviation: range, mean deviation, standard deviation or semi-interquartile range?
2What percentage of the data in the middle of a series does quartile deviation cover: 25%, 50%, 75% or 100%?
3Which formula gives the quartile deviation: \( Q_3 - Q_1 \), \( \frac{Q_3 - Q_1}{2} \), \( \frac{Q_3 + Q_1}{2} \) or \( \frac{Q_3 - Q_1}{Q_3 + Q_1} \)?
4If \( Q_1 = 10 \) and \( Q_3 = 30 \), what is the quartile deviation: 10, 20, 30 or 40?
5Which values are ignored when quartile deviation is calculated: all the values, the middle 50%, the first 25% and last 25%, or the average value?
6If the quartile deviation is 10 and the upper quartile is 30, what is the lower quartile: 40, 30, 20 or 10?
7Calculate the quartile deviation and its coefficient. Marks 0 - 10, 10 - 20, 20 - 30, 30 - 40, 40 - 50; number of students 4, 10, 20, 10, 6.
8Calculate the quartile deviation and its coefficient. Wages (in thousands of rupees) 0 - 5, 5 - 10, 10 - 15, 15 - 20, 20 - 25, 25 - 30; number of workers 4, 6, 3, 8, 12, 7.
9Calculate the quartile deviation and its coefficient. Weight (kg) 20 - 30, 30 - 40, 40 - 50, 50 - 60, 60 - 70, 70 - 80, 80 - 90; number of students 4, 5, 10, 15, 8, 7, 1.
10Calculate the quartile deviation and its coefficient. Marks \( 0 \le x < 10 \), \( 10 \le x < 20 \), \( 20 \le x < 30 \), \( 30 \le x < 40 \), \( 40 \le x < 50 \); number of students 5, 10, 15, 10, 5.
11Calculate the quartile deviation and its coefficient. Marks less than 20, 30, 40, 50, 60; number of students 5, 12, 27, 40, 50.
12Calculate the quartile deviation and its coefficient. Wages per hour more than Rs. 100, 200, 300, 400, 500; number of workers 100, 80, 60, 40, 20.
13The marks of 30 students in mathematics are: 12, 25, 36, 45, 18, 22, 33, 54, 42, 29, 38, 41, 15, 20, 48, 52, 30, 24, 19, 37, 44, 21, 35, 40, 14, 26, 49, 31, 23, 50. Taking 10 - 20 as the first class, present the data in a frequency table. Then find the first quartile, the third quartile, the quartile deviation and its coefficient.
14Can the value of the coefficient of quartile deviation be greater than 1?
15In which class does a weight of 45 kg belong when the classes are 40 - 45 and 45 - 50? Explain.
16Why is the coefficient of quartile deviation used instead of the quartile deviation when two series are compared?
17A student finding \( Q_1 \) in Worked Example 1 used cf = 135 instead of cf = 60. What went wrong, and what answer did they get?
18Why is the quartile deviation not affected by one very large value in the data?