Question

1. A company that makes language learning software wants to determine which of two approaches (Method A or Method B) to learning vocabulary would lead to the largest number of recalled words. The company wishes to evaluate the methods on 7 different languages (since languages differ in difficulty). Seven individuals, one per language, were recruited to learn words using Method A, and 7 individuals, one per language, were recruited to learn words using Method B.
   
   Suppose the company wishes to test whether there is a difference in the two methods at the 0.05 level. Which of the following value(s) would correctly mark the boundary of the rejection region? Select all that apply!

   		1.895
   		-2.447
   		2.447
   		-1.96
   		1.96
   		2.365

Answer 1

It is a matched pair design for t testing with two tailed hypothesis because researcher want to know whether there is any difference and difference testing is always two sided.

So, degree of freedom for matched pair design is df = n-1

where n is the sample size used and n = 7

this implies, degree of freedom = n-1 = 7-1 = 6

Using Excel function to find the t critical value

= T.INV.2T(probability,df)

where probability = 0.05 and df= 6

= T.INV.2T(0.05,6)

= 2.447

Since it is a two tailed hypothesis, we will consider 2.447 on both sides

So, t critical values are -2.447 and +2.447

Option B and C are correct.