Use the calculator provided to solve the following problemsS

Use the calculator provided to solve the following problems.

In a calculator, there is a function like- tcdf. The syntax is below

tcdf(lower_bound, upper_bound, df )

The function name may slightly differ from calculator to calculator but the syntax is almost the same.

P(-1.20<t<1.20)= 0.7543042

Calculator: tcdf(-1.20,1.20,18)

R-code:

pt(1.20,df=18)-pt(-1.20,df=18)
[1] 0.7543042

P(t>=c)=0.10 => P(t<c)=0.9

then c=1.312527

Use invT function / command in calculator to get this.

Calculator: invT(0.9,28)

R-code:

qt(0.9,df=28)
[1] 1.312527