A simple random sample consist of four observation 1, 3, 5, 7. What is the point estimate of population standard deviation?
A
2.3
✓
2.52
C
0.36
D
0.4
Answer
Correct option: B.
2.52
B Explanation: The point estimation of population standard deviation is sample deviation. $S =\sqrt{\frac{\left(x_i-\bar{x}\right)^2}{n-1}}$ $=\sqrt{\frac{(1-4)^2+(3-4)^2+(5-4)^2+(7-4)^2}{4-1}}$ $\left(\because \bar{x}=\frac{\Sigma x}{n}=\frac{16}{4}=4\right)$ $=\sqrt{\frac{9+1+1+9}{3}}=\sqrt{\frac{20}{3}}=2.52$
A sample of 50 pens is taken at random. Out of 50 pens we found 15 pens are of Cello, 17 are of Parker and 18 are of Reynolds. What is the point estimate of population proportion of Parker.
A
0.3
✓
0.34
C
0.36
D
0.4
Answer
Correct option: B.
0.34
B Explanation: Population proportion of Parker $=\frac{17}{50}=0.34$
An observed set of the population that has been selected for analysis is called:
✓
a sample
B
a process
C
a forecast
D
a parameter.
Answer
Correct option: A.
a sample
A Explanation: A selection of a group of individuals from a population in such a way that it represents the population is called as sample and the number of individuals in the sample is called the sample size.