- A6 students; 34 in all
- B10 students; 6 in all
- C10 students; 34 in all
- D8 students; 34 in all
Step-by-Step Solution
The bar over reaches . The total is the sum of all bar heights: .
Answer: C) 10 students; 34 in all
The histogram shows the weights of the students of a class in Pune. How many students weigh 40 kg or more but less than 45 kg, and how many students are there in the class altogether?
Class 9StatisticsStatistics and Probability
Key idea: Histogram vs bar graph
Both look like bars, but they differ:
**Bar graph**: For DISCRETE / categorical data (favourite colour, sport, etc.). Bars have GAPS between them. Width has no meaning.
**Histogram**: For CONTINUOUS / grouped data with class intervals. Bars TOUCH (no gaps), reflecting that the class boundaries are continuous. Bar WIDTH represents class size; HEIGHT represents frequency.
**Frequency polygon**: connect the midpoints (class marks) of the tops of histogram bars to form a line graph. Useful for comparing two distributions on the same axes.
**Key rule**: histogram bars must have no gaps; bar graph bars MUST have gaps.
**Bar graph**: For DISCRETE / categorical data (favourite colour, sport, etc.). Bars have GAPS between them. Width has no meaning.
**Histogram**: For CONTINUOUS / grouped data with class intervals. Bars TOUCH (no gaps), reflecting that the class boundaries are continuous. Bar WIDTH represents class size; HEIGHT represents frequency.
**Frequency polygon**: connect the midpoints (class marks) of the tops of histogram bars to form a line graph. Useful for comparing two distributions on the same axes.
**Key rule**: histogram bars must have no gaps; bar graph bars MUST have gaps.
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