JAMB Mathematics Past Questions & Answers - Page 325

1,621.

Find the standard deviation of 2,3,8,10 and 12

A.

3.9

B.

4.9

C.

5.9

D.

6.9

Correct answer is A

\(\begin{array}{c|c} x & (x - \varkappa) & (x - \varkappa)^2 \\ \hline 2 & -5 & 25 \\ \hline 3 & -4 & 16 \\ \hline 8 & 1 & 1 \\ \hline 10 & 3 & 9 \\ \hline 12 & 5 & 25 \\ \hline & & 76
\end{array}\)

S.D = \(\sqrt{\frac{(x - \varkappa)^2}{n}}\)

S.D = \(\sqrt{\frac{76}{5}}\)

S.D = 3.9

1,622.

Find the range of 4,9,6,3,2,8,10 and 11

A.

11

B.

9

C.

8

D.

4

Correct answer is B

Range = Highest Number - Lowest Number

Range = 11 - 2 = 9

1,623.

Find the median of 2,3,7,3,4,5,8,9,9,4,5,3,4,2,4 and 5

A.

9

B.

8

C.

7

D.

4

Correct answer is D

Arrange all the values in ascending order, 2,2,3,3,3,4,4,4,4,5,5,5,7,8,9,9

1,624.

The mean of seven numbers is 96. If an eighth number is added, the mean becomes 112. Find the eighth number.

A.

126

B.

180

C.

216

D.

224

Correct answer is D

\(\frac{x}{7} = \frac{96}{1}\) ==> \(\frac{672 + x}{8} = 112\)

Therefore x = 224

1,625.

Evaluate \(\int^{\frac{\pi}{4}}_0sec^2 \theta d \theta\)

A.

1

B.

2

C.

3

D.

4

Correct answer is A

\(\int^{\frac{\pi}{4}}_0sec^2 \theta d \theta\)

= \([\tan \theta]_{0} ^{\frac{\pi}{4}}\)

= \(\tan \frac{\pi}{4} - \tan 0\)

= \(1 - 0\)

= 1.