Fill up the blank:

For a histogram, _____ is a zig-zag line that is used when the scale on the x-axis doesn't start from $0$.

In an examination, $40\%$ of candidates got second class. When the data are represented by a pie chart, what is the angle corresponding to second class?

Coronavirus disease (COVID$-19$) is an infectious disease caused by the SARS-CoV$-2$ virus.

Most of the people who got infected with this virus have experienced mild to moderate respiratory illness and recovered soon. But, some people have become seriously ill and required medical attention. Older people who have other medical conditions like diabetes, chronic respiratory disease, or cardiovascular disease etc. will be infected easily and develop serious illness. Anyone, at any age, can get sick with Coronavirus and become seriously ill or die. 

During a survey, the ages of patients who are infected and admitted in a city hospital are recorded. The data is represented using the histogram as show below:

The age group of the lowest number of patients infected by Covid$-19$ is

Coronavirus disease (COVID$-19$) is an infectious disease caused by the SARS-CoV$-2$ virus.

Most of the people who got infected with this virus have experienced mild to moderate respiratory illness and recovered soon. But, some people have become seriously ill and required medical attention. Older people who have other medical conditions like diabetes, chronic respiratory disease, or cardiovascular disease etc. will be infected easily and develop serious illness. Anyone, at any age, can get sick with Coronavirus and become seriously ill or die.

During a survey, the ages of patients who are infected and admitted in a city hospital are recorded. The data is represented using the histogram as show below:

The average of the number of patients in each group is

For drawing a frequency polygon of a continuous frequency distribution, we plot the points whose ordinates are the frequencies of the respective classes and abscissa are respectively: