Statistics Practice 2: Median of Grouped Data

Cumulative Frequency

Question 1mcq

In step-deviation method, if

a=35

, class width

h=10

,

\sum f_i u_i=18

and

\sum f_i=30

, what is the mean?

A.

29

B.

41

C.

35.6

D.

53

Question 2mcq

Why is step-deviation method convenient when all class widths are equal?

A.It uses coded deviations, making calculations smaller.

B.It avoids using frequencies.

C.It gives only an approximate mean.

D.It works only for ungrouped data.

Question 3mcq

Frequencies are

3,5,8,4

. What are the less-than cumulative frequencies?

A.

3,5,8,4

B.

20,17,12,4

C.

8,13,17,20

D.

3,8,16,20

Question 4mcq

In a grouped table, why do we calculate cumulative frequency before finding the median?

A.To remove the modal class.

B.To calculate arc length.

C.To locate the class containing the

N/2

th observation.

D.To find the class mark.

Question 5mcq

If

N=50

, then the median class is the class whose cumulative frequency first becomes at least:

A.

100

B.

25

C.

50

D.

10

Median Formula

Question 6mcq

Cumulative frequencies are

6,14,29,40

and

N=40

. Which class is the median class?

A.The third class

B.The first class

C.The second class

D.The fourth class

Question 7mcq

For a median class,

l=20

,

N=50

,

cf=18

,

f=14

,

h=10

. What is the median?

A.

30

B.

20

C.

28

D.

25

Question 8mcq

In the median formula, what does

cf

represent?

A.Total frequency

B.Class width

C.Cumulative frequency before the median class

D.Frequency of the median class

Question 9mcq

For highly skewed income data, which measure often represents the typical value better than the mean?

A.Upper limit

B.Median

C.Class width

D.Frequency

Question 10mcq

A student chooses the class after

N/2

even though the current cumulative frequency already crosses

N/2

. What should be corrected?

A.Choose the first class whose cumulative frequency is at least

N/2

.

B.Always choose the last class.

C.Use

2N

instead of

N/2

.

D.Ignore cumulative frequency.