Punjab State Board PSEB 7th Class Maths Book Solutions Chapter 3 Data Handling Ex 3.1 Textbook Exercise Questions and Answers.

## PSEB Solutions for Class 7 Maths Chapter 3 Data Handling Ex 3.1

1. Find the mean of the following data :

Question (i).

3, 5, 7, 9, 11, 13, 15

Answer:

Mean = \(\frac{3+5+7+9+11+13+15}{7}\)

= \(\frac {63}{7}\)

= 9

Question (ii).

40, 30, 30, 0, 26, 60

Answer:

Mean = \(\frac{40+30+30+0+26+60}{6}\)

= \(\frac {183}{6}\)

= 9

2. Find the mean of the first five whole numbers.

Answer:

The first five whole numbers are : 0, 1, 2, 3, 4

Mean = \(\frac{0+1+2+3+4}{5}\)

= \(\frac {10}{5}\)

= 2

Hence, the mean of first five whole numbers = 2

3. A batsman scored the following number of runs in six innings :

36, 35, 50, 46, 60, 55

Calculate the mean runs scored by him in an inning.

Answer:

Mean runs

= \(\frac{36+35+50+46+60+55}{6}\)

= \(\frac {282}{6}\)

Hence, the mean runs scored by batsman in an innings = 47

4. The ages in years of 10 teachers of a school are :

32, 41, 28, 54, 35, 26, 23, 33, 38, 40

(i) What is the age of the oldest teacher and that of the youngest teacher ?

(ii) What is the range of the ages of the teachers ?

(iii) What is the mean age of these teachers ?

Answer:

Arranging the ages in ascending order, we get

23, 26, 28, 32, 33, 35, 38, 40, 41, 54

(i) Age of the oldest teacher = 54 years Age of the youngest teacher 23 years

(ii) Range of the ages = 54 – 23 = 31

(iii) Mean age of the teachers

= \(\frac {350}{10}\)

= 35 years.

5. The rain fall (in mm) ip a city on 7 days of a certain week was recorded as follows :

(i) Find the range of the rainfall in the above data.

(ii) Find the mean rainfall for the week.

(iii) How many days had the rainfall less than the mean rainfall ?

Answer:

(i) Arranging the rainfall (in mm) in ascending order, we get

Highest Rainfall = 20.5 mm

Lowest Rainfall = 0.0 mm

Range of the rainfall = 20.5 mm – 0.0 mm

= 20.5 mm.

(ii) Mean Rainfall

= \(\frac{0.01+12.2+2.1+0.0+20.5+5.5+1.0}{7}\)

= \(\frac {41.31}{7}\)

= 5.9 mm.

(iii) Number of days having rainfall less than mean rainfall = 5 days.