Question

A medical researcher is interested in whether patients' left arms or right arms are longer. If 13 patients participate in this study (so that n left arms and n left arms are measured), how many degrees of freedom should the researcher use in her t-test critical value?

a)24

b)12

c)13

d)25

Using the z-table (Table E), find the critical value (or values) for a α = .14 right-tailed test.-

a)0.5402

b)0.7879

c)1.5758

d)1.0803

Answer 1

Solution :

1) n = 13

degrees of freedom = n - 1 = 13 - 1 = 12

correct option is = b)

2) This is the right tailed test,  

The null and alternative hypothesis is ,

H0 :   = 0

Ha : > 0

α = 0.14

P(Z > z) = 0.14

= 1 - P(Z < z) = 0.14  

= P(Z < z) = 1 - 0.14

= P(Z < z ) = 0.86

= P(Z < 1.0803 ) = 0.86  

z = 1.0803

correct option is = d)