ht_twosample_mannwhitney(A, B, alpha, type)

Hypothesis test for two population means using Mann-Whitney test. Arrays A and B store the samples. alpha is the significance level. Parameter type can be 0 (left tail), 1 (right tail), or 2 (both tails).
Assumes samples are independent and have the same shape.

See also ht_twosample_tnonpooled ht_twosample_tpaired ht_twosample_tpooled 

Example

(See NOTE below)

a=(139, 118, 164, 151, 182, 140, 134 )

( 139 118 164 151 182 140 134 )

b=(142, 109, 130, 107, 155, 88, 95, 104)

( 142 109 130 107 155 88 95 104 )

ht_twosample_mannwhitney(a, b, .05, 1)

Mann-Whitney-Wilcoxon Test.

Hypothesis test for two population means.

Ho : m1==m2

Ha : m1>m2

Significance level : 0.05 (5.0%)

Results:

Test statistics W : 74.0

Critical right value found is 70.0

Reject the null hypothesis.

NOTE: The data used in this example was taken from the textbook Introductory Statistics 6th Ed. by Neil A. Weiss with kind permission of Addison Wesly Longman, Inc. (AWL). AWL does not endorse nor it supports the Calcugator.