Refer to the accompanying data display that results from a sample of airport data speeds in Mbps. Complete parts(a) through(c) below.

TInterval

(13.046,22.15)

x overbar

xequals

=17.598

Sxequals

=16.01712719

nequals

=50

a. What is the number of degrees of freedom that should be used for finding the critical value t Subscript alpha divided by 2

b. Find the critical value t Subscript alpha divided by 2 corresponding to a95% confidence level.