Statisticshard · Past Paper
The mean age of 30 students is 15 years. If the teacher's age is included, the mean increases by 1 year. Teacher's age is:
A45
B31
C46
D16
✓ Correct Answer: C — 46
Total age = 30*15 = 450. New total = 31*16 = 496. Teacher = 496 - 450 = 46.
Share this question
More from Statistics
- Find the mode of the following distribution: Class: 0-10, 10-20, 20-30; Freq: 5, 12, 8.
- If the probability of an event is p, what is the probability of its complement?
- If the mean of observations $x_1, x_2, ... x_n$ is $\bar{x}$, then $\sum_{i=1}^n (x_i - \bar{x})$ is:
- If the mean of first $n$ natural numbers is $3n/5$, then $n$ is:
- A die is thrown once. What is the probability of getting an odd number?