There are two letters X and Y. If repetitions such as XX are ...

[theo]

There are two letters X and Y. If repetitions such as XX are permitted, how many two-letter permutations are possible?
 
  A) 2
  B) 4
  C) 6
  D) 8

Question 2

Which of the following is an appropriate null hypothesis?
 
  A) H0 : x - y  0
  B) H0 : Px > Py
  C) H0 : x - y < 0
  D) H0 : 2x =2y

[peilian]

Answer to Question 1

B

Answer to Question 2

D

[theo]

Thanks for the timely response, appreciate it

[dreamfighter72]

Gracias!