STATISTICS - Jamb Mathematics Past Questions and Answers

Question 156:

• JAMB 1993

Calculate the standard deviation of the following data: 7, 8, 9, 10, 11, 12, 13.

A. 2
B. 4
C. 10
D. 11

Question 157:

• JAMB 1993

The chances of three independent events X, Y, Z occurring are \(\frac{1}{2}\), \(\frac{2}{3}\), \(\frac{1}{4}\) respectively. What are the chances of Y and Z only occurring?

A. \(\frac{1}{8}\)
B. \(\frac{1}{24}\)
C. \(\frac{1}{12}\)
D. \(\frac{1}{4}\)

Question 158:

• JAMB 1994

The mean of twelve positive numbers is 3. When another number is added, the mean becomes 5. Find the thirteenth number

A. 29
B. 26
C. 25
D. 24

Question 159:

• JAMB 1994

\(\begin{array}{c|c} \text{Age in years} & 10 & 11 & 12 \\ \hline \text{Number of pupils} & 6 & 27 & 7\end{array}\)
The table above shows the number of pupils in each age group in a class. What is the probability that a pupil chosen at random is at least 11 years old?

A. \(\frac{27}{40}\)
B. \(\frac{17}{20}\)
C. \(\frac{33}{40}\)
D. \(\frac{3}{20}\)

Question 160:

• JAMB 1994

\(\begin{array}{c|c} x & 1 & 2 & 3 & 4 & 5 \\ \hline f & y + 2 & y - 2 & 2y - 3 & y + 4 & 3y - 4\end{array}\)
This table shows the frequency distribution of a data if the mean is \(\frac{43}{14}\) find y

A. 1
B. 2
C. 3
D. 4