Answer:
The correct answer is option 'D': Standard error of the mean.
Step-by-step explanation:
If we carry out observations that are random in nature the mean of the data is the average value which gives us an idea about the value about which the data is spread about.
The standard deviation gives us the distribution of the data around the mean thus data with a low standard deviation means that the data point's are closer to mean. A larger value of standard deviation means that the data is highly discrete or we can say that the variations in the data points is large.
the concept of standard deviation is highly useful while carrying out results of measured observations as it gives us a estimate of the standard error of the mean.