If n 1 = 6, n 2 = 8 and a = 0.05 2 tail , U crit value is _________.
A) 8
B) 40
C) 6
D) 42

Question

Quizplus · Accepted Answer

To find the U crit value, first we need to calculate the U value using the formula:

U = n1n2 + (n1(n1+1))/2 - R1

where R1 is the rank sum of the first group.

Since we only have the sample size and not the actual scores, we cannot calculate R1. However, we can calculate the smallest and largest possible values of R1 based on the sample size and assuming that the largest and smallest scores are in the second group.

The smallest possible value of R1 is n1, since all scores in the first group are smaller than the smallest score in the second group. 
So, U will be:

U = n1n2 + (n1(n1+1))/2 - n1
U = 6*8 + (6*7)/2 - 6
U = 42

The critical value of U is the value at which we reject the null hypothesis (that there is no difference between the two groups) at the given significance level (a). For a two-tailed test with a = 0.05, we need to find the critical value that corresponds to the area in both tails, which is equal to (1-a)/2 = 0.025.

Looking up the critical values of U for a two-tailed test with n1 = 6 and n2 = 8 and a = 0.05 in a table, we find that the critical value is 8. Therefore, the answer is A.

If N 1 = 6, N 2 = 8 and a =