Business Statistics

Chapter 9 | Statistical Inference: Estimation for Single Populations 291

distribution for large samples, even in cases where standard deviation is unknown. Figure 9.11 exhib-

its the comparison of standard normal curve with two t curves with sample size n = 10 and n = 22.

9.6.2  Degrees of Freedom

As we have discussed, for different degrees of freedom, the t distribution is unique. For example, for a

t distribution with 10 degrees of freedom and

0.05

2

=



, the value from the t distribution table is t

0.05

=

1.812. For a t distribution with 20 degrees of freedom and

0.05

2

=



, the tabular value of t

0.05

= 1.725.

From the t distribution table, it ...