Statisticshard · Past Paper
If the mean of 5 observations $x, x+2, x+4, x+6, x+8$ is 11, then the mean of first three observations is:
A9
B11
C7
D8
✓ Correct Answer: A — 9
Mean of $x, x+2...x+8$ is $x+4$. $x+4=11 \Rightarrow x=7$. First three are 7, 9, 11. Mean = 9.
Share this question
More from Statistics
- A bag has 3 red and 5 black balls. If two balls are drawn one after another without replacement, what is the probability that both are red?
- If two dice are thrown, what is the probability that the sum of the numbers is 7?
- If the mean of n observations is X, and each observation is multiplied by 3, the new mean is:
- A box contains 4 red, 5 black, and 6 white balls. One ball is drawn at random. What is the probability that the ball is not black?
- In a moderately skewed distribution, the values of Mean and Median are 12 and 13 respectively. The value of Mode is: