Statistics And Probability Question 507
Question: If the values $ 1,,\frac{1}{2},,\frac{1}{3},,\frac{1}{4},,\frac{1}{5},,…..,\frac{1}{n} $ occur at frequencies 1, 2, 3, 4, 5, ?.,n in a distribution, then the mean is
Options:
A) 1
B) n
C) $ \frac{1}{n} $
D) $ \frac{2}{n+1} $
Show Answer
Answer:
Correct Answer: D
Solution:
Mean $ =\frac{1.1+\frac{1}{2}.2+\frac{1}{3}.3+\frac{1}{4}.4+\frac{1}{5}.5+…..+\frac{1}{n}.n}{1+2+3+…..+n} $ $ =\frac{1+1+1+1+…..+1}{\frac{n(n+1)}{2}} $ $ =\frac{n}{\frac{n(n+1)}{2}}=\frac{2}{n+1} $ .
BETA
