Answer
a)39
b)2.023
c)The number of degrees of freedom for a collection of sample data is the number of sample values that are free to vary after certain
restrictions have been made on all data values.
Work Step by Step
a) degree of freedom=sample size-1=40-1=39
b) $\alpha=1-(confidence \ level)=1-0.95=0.05.$
According to the table: $t_{\alpha/2}=t_{0.025}=2.023$
c) The number of degrees of freedom for a collection of sample data is the number of sample values that are free to vary after certain
restrictions have been made on all data values.
