Answer: 18
Step-by-step explanation:
Given : A simple random sample of 5 observations from a population containing 400 elements was taken, and the following values were obtained (12 18 19 20 21).
Then , the sample mean = [tex]\dfrac{\text{Sum of observations}}{\text{Number of observations}}[/tex]
sample mean [tex]=\dfrac{12 +18 +19+ 20+ 21}{5}=18[/tex]
Hence, A point estimate of the mean is 18.