Q1
In a one hour class, the number of students are active during the session as follows:
Class time
1-10
Number of 11
students
10-20
29
20-30
18
30-40
4
40-50
5
50-60
3
How many students are averagely active during the class? Which time students are more
active?
[5]
Q.4. Set A) The frequency table of the monthly salaries of 20 people is shown below.
salary(in $)
frequency
3500
5
4000
8
4200
5
4300
2
a) Calculate the mean of the salaries of the 20 people. [1]
b) Calculate the variance of each value from mean [2]
b) Calculate the standard deviation of the salaries of the 20 people. [1]
Q.4. Set B) The owner of the Five star restaurant is interested in how much people spend at
the restaurant. He examines 10 randomly selected receipts for parties of four and writes
down the following data.
44, 50, 38, 96, 42, 47, 40, 39, 46, 50
a) What is the average amount of money spent by people in this restaurant?
b) What is the difference between mean with actual value spent by people in
this restaurant?
c) Calculate the amount how much people spend at the restaurant? Mention
lowest money to highest money spent by the customers. [4]
Q.4. Set C) In a classroom, following is the English marks distribution for the students.
Marks
>No. of students
>1-3
>40
>3-5
>30
>5-7
>20
>7-9
>10
a) What is the average marks of the class?
b) How many students are above the average marks?
If we consider the average marks for B grade, what is the standard deviation of the marks?
c)
Write down each step and assumptions if any.
[4]
