1The marks of two students are: A: 68, 70, 72, 69, 71, 70, 70 and B: 40, 95, 50, 90, 60, 70, 80. Whose result is better?
2How can you tell whose result is better?
3Find the mean marks of student A and student B.
4When the mean marks of two students are the same, how can they be compared?
5Find the standard deviation of the marks of student A and student B.
6Students A and B have almost the same mean, but the standard deviation of A's marks is about 1.2 while that of B's marks is about 19. What conclusion can be drawn when the means are the same but the standard deviations differ?
7Why is standard deviation taken as the most suitable measure of dispersion?
8What is variance? How is it related to standard deviation?
9Name four fields where standard deviation is used, and say what it does in each.
10Define the coefficient of standard deviation. Why is it needed?
11Define the coefficient of variation and write its formula. Why is it written as a percentage?
12The mean of a set of data is 25 and its standard deviation is 5. Find the coefficient of standard deviation and the coefficient of variation.
13Factory A fills packets with a mean weight of 500 g and a standard deviation of 10 g. Factory B fills packets with a mean weight of 250 g and a standard deviation of 8 g. Which factory fills its packets more uniformly?
14The coefficient of variation of a data set is 5% and its standard deviation is 3. Find the mean.