Experts have designed these Class 7 Maths Notes and Part 2 Chapter 5 Connecting the Dots Class 7 Notes for effective learning.
Class 7 Maths Chapter 5 Connecting the Dots Notes
Class 7 Connecting the Dots Notes
→ Data handling is the process of collecting, organising, and interpreting information to make it meaningful. In everyday life, we encounter various types of data, such as scores, heights, rainfall, or expenses. To understand data easily, we often represent it using tables, graphs, or charts.
Once data is collected, it can be organised in tables, pictographs, bar graphs, or line graphs to make it easy to read and compare. Graphical representation like, pictograph, dot plot, bar graph, etc., helps us quickly understand patterns and trends. Representative values like mean, median, help us to summarize large sets of data with a single number.
→ Statistics refers to the study of collecting, organising, analysing, interpreting, and presenting data.
→ Tables organize data in rows and columns for clarity.
→ Represent each data point as a dot above a number line to show frequency is called dot plotting.
→ Mean is the average of all data values. It is calculated as:
Mean \(=\frac{\text { Sum of all the values in the data }}{\text { Number of values in the data }}\)
→ Dot plots help us get a quick glimpse of the variability of the data-minimum, maximum, range, and how data is clustered or spread out.
→ The Median is the number in the middle of any sorted data. If there are an even number of values, then the median is the average of the two middle numbers.
→ An outlier is a value in a data set that is much smaller or much larger than the other values.
- Outliers greatly affect the mean because it depends on the sum of all values.
- Outliers do not affect the median much, as it depends on the middle value.
→ When the data is more balanced or uniformly spread out, the mean and the median are close to each other.
→ When the outlier is on the lower end, the mean shifts in that direction.
→ When the outlier is on the higher end, the mean shifts in that direction.
→ Mean and Median are called measures of central tendency, i.e., the tendency of the values to pile up around a particular value.
→ Representing data using pictures is called data visualisation.
→ In bar graphs we represent data using rectangular bars.
→ The length or height of each bar represents the value of the data.
→ Bars can be vertical or horizontal.
→ We compare two sets of data for the same categories using side-by-side bars. Such graph is called double bar graph. It is also called clustered column graph.
→ Each category has two bars placed side by side, usually in different colors or patterns.
→ These graphs can be used to compare and visualise values across categories and across time.