Page 296 - Start Up Mathematics_7

8. The median of the marks scored by 5 students is 70. If the marks of the student scoring the
highest are increased by 2, then the value of the median:

(a) increases by 2 (b) decreases by 2 (c) remains same (d) is multiplied by 2
9. The mean of a series of individual observation is 12. If each observation is increased by 1,
then the value of the new mean:
(a) increases by 1 (b) decreases by 1 (c) remains same (d) can’t say

10. A shopkeeper keeps a weekly record of sales of different sizes of shirts. The central tendency
which cannot be ignored while placing an order for procurement of shirts is:

(a) mean (b) median (c) mode (d) range
11. One hundred students of Class VII were asked to name their favourite colour and the data was
converted to a bar graph. The most preferred colour was represented by the height of the:

(a) lowest bar (b) average of bars (c) bar drawn first (d) highest bar

12. The median of the first 99 natural numbers is:
(a) 48 (b) 49 (c) 50 (d) 51

solve Mentally
True or False

1. The value of the arithmetic mean is not affected by extreme values.

2. Median of raw data is not affected by extreme values.
3. Mode is the positional average.
4. Mode is the value which occurs the maximum number of times in a data.

5. Mean is always one of the observations in the data.
6. Median is one of the observations in the data if the number of observations are odd.

7. The value of mean, median and mode can never be equal.
8. The value of mean always lies between the minimum and maximum value of the data.

9. The value of mode can never be the lowest or highest observation of the data.
10. The width of the bars is not of much significance. It is only for visual impact.

11. The length of the bars is significant as it represents the frequency.
12. In a bar chart, the scale of 1 unit length represents 100 students. Then 500 students are
represented by a bar of length 5 units.

Fill in the Blanks
1. The numbers 1, 2 and 3 repeat as many times as their value. The mode and median of the
observations are ___________ and ___________ respectively.

2. The ___________ divides a data into two equal halves.

3. The mode of series of 7 observations is 50. If by mistake the whole series is repeated once
again, then the mode of 14 observations so obtained is ___________.

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