1.  Which of the following statements is incorrect?

2. Which of the following statements is/are true ?

1. The mean of a series remains unaffected if an observation equal to mean is included in the series.
2. 50th percentile is median.
3. Q₁ equals the 25th percentile.
4. A.M. can be calculated for a distribution with open ends.

3. Which of the following is not true ?

4. Which of the following statements is/are correct ?

1. Measures of central tendency are called averages of first order.
2. Histogram is used to find mode graphically.
3. If the mean, median and mode of a data set are equal, then the distribution of the data is symmetrical.
4. Median is the point below which 50% of the data items fall.

5. Which of the following is not correct ?

6. Which of the following statements is/are correct ?

1. Mode is the value with maximum frequency in the data.
2. Mean is based on all the observations.
3. 75% observations in a distribution are greater than Q₃.
4. 80% of observations of a series lie between first and ninth deciles.

7. Mean is not used in-

8. If different articles are purchased at different rates by spending equal amount on each article, the average rate of purchase is given by-

9. In averaging index numbers, which of the following averages is used ?

10. In compound interest calculations average rate of interest against varying rate of interest is calculated by-