WAEC Mathematics Past Questions & Answers - Page 309

1,541.

The mean of 30 observations recorded in an experiment is 5. lf the observed largest value of 34 is deleted, find the mean of the remaining observations

A.

5

B.

4

C.

3.9

D.

3.4

E.

3.0

Correct answer is B

x = 5, \(\frac{\sum {fx}}{\sum {f}}\) =

5= \(\frac{\sum {fx}}{30}\)

\(\sum {fx}\) = 5 x 30 = 150; 150 - 34 = 116

\(\sum {f}\) = 29
\(\sum {fx}\) = 116

= \(\frac{116}{29}\) = 4

1,542.

Which of the following is not a measure of dispersion?

A.

Mode

B.

Mean deviation

C.

Range

D.

interquartile range

E.

Standard deviation

Correct answer is A

No explanation has been provided for this answer.

1,544.

P = {2, 1,3, 9, 1/2}; Q = {1,21/2,3, 7} and R = {5, 4, 21/2}. Find P∩Q∩R

A.

(21/2)

B.

C.

(1, 3, 7)

D.

(4)

E.

(5,7,9)

Correct answer is B

No explanation has been provided for this answer.

1,545.

P={2, 1,3, 9, 1/2}; Q = {1,21/2,3, 7} and R = {5, 4, 21/2}. Find P∪Q∪R

A.

(21/2)

B.

(1, 9)

C.

(1, 2, 3, 4, 5, 6, 7)

D.

(5, 4, 21/2)

E.

(1/2, 1, 2, 21/2, 3, 4, 5, 7, 9)

Correct answer is E

P = {2,1,3,9,1/2}; Q = {1,21/2,3,7}
R = {5,4,212}
P∪Q∪R = {1/2,1,2,21/2,3,4,5,7,9}

= {1/2,1,2,21/2,3,4,5,7,9}