In confidence interval calculation, what is the degree of freedom used if the sample size is 70?

In the context of calculating confidence intervals, especially when working with sample means and applying the t-distribution, the degrees of freedom play a crucial role. The degrees of freedom is typically calculated as the sample size minus one.

In this case, the sample size is 70. To determine the degrees of freedom, you subtract one from the sample size, which gives you 70 - 1 = 69. This value is necessary to refer to the correct t-distribution table for critical values that will be used in constructing the confidence interval.

Using this degree of freedom helps ensure that the confidence interval accurately reflects the variability and characteristics of the sample data. Thus, the correct degree of freedom to use in this situation is indeed 69.