Exercise 4 – Biostatistics
I. Choose the best answer:
1. In an exclusive class interval
(a) the upper class limit is exclusive.
(b) the lower class limit is exclusive.
(c) the lower and upper class limits are exclusive.
(d) none of the above.
2. If the lower and upper limits of a class are 10 and 40 respectively, the mid points of the
class is
(a) 15.0 (b) 12.5 (c) 25.0 (d) 30.0
3. Class intervals of the type 30-39,40-49,50-59 represents
(a) inclusive type (b) exclusive type
(c) open-end type (d) none.
4. The class interval of the continuous grouped data is
10-19 20-29 30-39 40-49 50-59
(a) 9 (b)10 (c) 14.5
(d) 4.5
5. Raw data means
(a) primary data (b) secondary data
(c) data collected for investigation (d)Well classified data.
II. Fill in the blanks:
6. H.A.Sturges formula for finding number of classes is ________.
7. If the mid-value of a class interval is 20 and the difference between two consecutive
midvalues is 10 the class limits are ________ and ________.
8. The difference between the upper and lower limit of class is called ______.
9. The average of the upper and lower limits of a class is known as _________.
10. Number of observations falling within a particular class interval is called __________ of
that class
Mrs.Amal Zahran
Majma’ah University
Page 1
Exercise 4 – Biostatistics
17. 25 values of two variables X and Y are given below. Form a
two-way frequency table showing the relationship between the
two. Take class interval of X as 10-20,20-30,….. and Y as 100-200,200-300,…
Mrs.Amal Zahran
Majma’ah University
Page 2