Page 121 - Data Science class 10
P. 121
Example 1.2: Consider a farewell event of mixed classes having only ten students. You have conducted the survey
by asking students if they like eating pizza. You record the data in the format given below.
Name of student Age Likes Pizza?
Participant no 1 18 <Yes>
Participant no 2 6 No
Participant no 3 13 <Yes>
Participant no 4 9 No
Participant no 5 12 <Yes>
Participant no 6 14 <Yes>
Participant no 7 19 <Yes>
Participant no 8 8 No
Participant no 9 16 No
Participant no 10 12 <Yes>
If you now break down the data into age categories of (5 – 10 years), (10 – 15 years), and (15 – 20 years), and plot
the number of students who like and dislike pizzas, then the table would look like below:
Age Group Likes Pizza Does not like pizza
5 to 10 0 3
10 to 15 4 0
15 to 20 2 1
The row category in this example is “5-10 years”, “10-15 years” and “15-20 years”. The column category is their
choice “Likes pizza” or “Does not like pizza”. Each cell tells us the number (or frequency) of the students. There is a
lot of information that we can get from this small table. For example,
Q. How many students were questioned?
Answer: 10
Q. How many students liked pizzas?
Answer: 6
Q. In which age group do students like pizzas the most?
Answer: 10 – 15
Let us now have a look at another example:
Example 1.3: Two-way frequency tables show how many data points fit in each category. The columns of the table
tell us whether the student is a male or a female. The rows of the table tell us whether the student prefers dogs,
cats, or doesn't have a preference. Each cell tells us the number (or frequency) of students.
Preference Male Female
Prefer cats 36 22
Prefer dogs 8 26
No preference 2 6
Total 46 54
Use of Statistics in Data Science 119

