Question

1. what are 3 ways of calculating R2 (squared) ?

2. What is the sampling error?

Answer 1

We calculate the R^{​​​​​​2} by following method.

1.The coefficient of determination, R2, is similar to the correlation coefficient, R. The correlation coefficient formula will tell you how strong of a linear relationship there is between two variables. R Squared is the square of the correlation coefficient, r (hence the term r squared).

2.The R-squared formula is calculated by dividing the sum of the first errors by the sum of the second errors and subtracting the derivation from 1. Here’s what the r-squared equation looks like.

R-squared = 1 – (First Sum of Errors / Second Sum of Error)

3.

​​​​​where, SS_Err is the sum of squares due to error and the SS_Tot is the sum of squares due to total.

2.In statistics, sampling errors are incurred when the statistical characteristics of a population are estimated from a subset, or sample, of that population. A sampling error is a statistical error that occurs when an analyst does not select a sample that represents the entire population of data and the results found in the sample do not represent the results that would be obtained from the entire population.

Sampling error is the difference between a population parameter and a sample statistic used to estimate it. For example, the difference between a population mean and a sample mean is sampling error. Sampling error occurs because a portion, and not the entire population, is surveyed. Probability sampling methods, where the probability of each unit appearing in the sample is known, enable statisticians to make probability statements about the size of the sampling error.