Question

 Two independent groups of patients were given Drug X and Drug Y. The recovery times (in days) are as follows:

           
Drug X 8 10 9 7 11
Drug Y 6 7 5 8 6

 (i) State the null and alternative hypotheses.

(ii) Explain why the Mann–Whitney U test is appropriate for this data.

(iii) Perform the test at the 5% level of significance and draw a conclusion. 

18 Mar 2026
Answer :
Word Count : 932
The problem involves comparing the recovery times of two independent groups of patients treated with Drug X and Drug Y, and the objective is to determine whether there is a statistically significant difference between the two treatments using the Mann–Whitney U test, interpreted within the broader frameworks of classical and Bayesian inference. The null hypothesis in this context states that there is no difference between the distributions of recovery times for the two drugs. In other words, the probability that a randomly selected patient from Drug X has a longer recovery time than a randomly selected patient from Drug Y is equal to the probability of the reverse. Symbolically, this can be expressed as (H_0: F_X = F_Y), where (F_X) and (F_Y) denote the distributions of recovery times for Drug X and Drug Y respectively. The alternative hypothesis states that the two distributions are not equal, implying that one drug tends to produce systematically shorter or longer recovery times than the other. This can be written as (H_1: F_X \neq F_Y), reflecting a two-tailed test. The Mann–Whitney U test is appropriate for this data for several important reasons. First, the sample sizes are small, with only five observations in each group, making it difficult to reliably assess normality assumptions required for parametric tests such as the independent samples t-test. Second, the data are measured on at least an ordinal scale, as recovery times can be ranked meaningfully. Third, the Mann–Whitney test does not require the assumption of normal distribution; instead, it is
____ _____ _______ _________ _______ ___ _________ _______ ____ __________ _____.
________ _____ ________ _____ ____ ______.
______ ______ _________ ________ __________ _________ _____ ______ _________ _____ _____.
______ ___ ______ __________ ________ _________ __________ _______ __________ ______ ____.
_________ __________ ____ ____ _______ _____ _______ ________ ____ __________ ___.
_____ ______ _________ ________ _____ __________ ______.
______ ________ _______ ____ ________ ________ ________ _____ ___ _________ _______.
___ ______ _________ ___ _____ _____ ____ _________.
_______ _______ _________ ________ ________ ___.
__________ ___ __________ _________ ____ _____ ___.
____ ________ ____ ___ ____.
________ _____ ___ ________ ________ ____ ___ ________ ___ _________ ________ _________.
__________ ___ ____ ________ ___ ___ _________ ________ _________ ____ _____.
_____ _____ _______ ____ ________ _____ ________ __________ ____ ___ ______ ______.
__________ _________ ____ __________ _________ _____ _____ ___ ______ _______.
________ ___ _____ _____ ________ ______ ___ _____ ____ ___.
_______ __________ ___ ________ ________.
________ ______ ___ ________ ______.
_______ _________ ________ ____ ___ _______ ____ ______ ________ _________ ________.
_____ ___ _________ __________ ____ ___ ___ ______ _________ ______ _________.
__________ ____ ____ ___ _______ ________ _____ _____ _____ ______ _________.
_______ _____ ____ ________ _______ _______ _______ _______ _________.
_____ _______ _______ ________ ____ ____ _____ ____ _________ ___.
_______ ______ _______ _________ _______ __________.
__________ ___ ________ _____ _________ _____.
____ ______ _______ _________ ________ _______ _______.
__________ _______ ____ ____ _________ _________.
_______ ___ ________ ____ _____ _________ _________ ___ _____ _____ ______.
______ _____ ________ ____ ________ _____ _______ _______ ____ _____.
_______ ___ ____ __________ _______ _______ _______.
__________ ________ __________ ______ _______ ____ ___ ______ _________.
________ ____ _____ ___ ____ _____ _______ ______ ________ __________ __________ ________.
_______ ____ ______ _______ ________ _______ ________ _______ _______.
_____ __________ _______ ________ ______ _______ _____ _______ __________ ________ _____ _________.
____ ______ ________ _______ ___ __________ ___.
_____ _____ ___ _____ ___ _____ ___.
_________ ____ ______ _______ ______ ________ __________ ____.
________ ______ ________ ____ ________ ____ _____ ____ __________ _____.
_______ ___ _____ __________ _________ _________ _________ _____.
______ ______ _________ _________ ___ _______.
___ _____ _____ _________ ________ _____ _________.
_____ ____ _______ _____ __________.
_________ ___ ____ ______ _________.
_______ ___ ____ ______ _________ ________ ____.
_______ ________ ____ _____ _____ _________.
____ _________ __________ _______ _____ ____ _________ ____.
_____ ______ _________ __________ ________ ___ ____ ________ ___ _______ _________.
_______ _____ _______ ____ _______ _________ ________ _____ _____ ____.
_______ _____ _____ ________ ____ ___ _________ ______ __________ ________ _______.
________ _____ __________ ____ ________ ______ _____ _________ _________ ______.
_______ _______ ______ ______ ________ ________ ______ __________.
__________ ________ _____ ____ ________ _________ _________.
___ ________ _____ ________ _______ __________ ____ _____ ______ _______.
____ ____ ______ ________ ___ ___ _______ __________.
_______ __________ _____ _______ __________ _______ _________ _______ ___ _____ _________ ______.
__________ __________ ________ __________ _______.
_________ ______ _______ __________ ______.
_______ ______ __________ __________ ____ _____ ______ ____.
________ _____ ______ ________ _________ ____ _______ ______ _____ ____ _____ _________.
__________ ______ _____ _________ ____ ________ ___ ______ ___ __________ __________ ________.
_________ ___ ______ ________ ________ _________.
______ _________ ______ _____ __________ _____ ______ ____.
_________ ______ _______ _______ _______ _____.
________ _________ ______ ____ _________.
________ _______ _____ __________ ________ _____ _____.
_____ _____ ____ ____ ____ ________ _________.
__________ _____ __________ ____ _______.
____ ________ ____ ________ ______ ________ _________ _____ __________ ___ __________.
_________ ________ _______ ________ ______ _____ _______ ____ ______ ________ ____.
__________ ______ __________ ________ ______.
________ __________ _____ _____ ______ _____ _________ ________.
______ _______ ________ ____ ______ _______ ________ _______ _______ ____.
_______ _________ ___ ____ _____ ____.
______ ____ ______ _____ _______ ___ ____ _______ ______.
____ __________ _________ ________ _____ ________ ________ ____ __________ __________ _____.
________ __________ _________ ____ ____ ____ __________.
__________ ___ _________ __________ _______ _______ _______.
________ ____ _____ _______ ____ _______ ______ _______ _______ ________ ____.
______ _______ _________ ____ ________ __________ ___ _________ _______ __________ _____ _________.
_______ __________ ____ ___ ___ ____ ______ ____.
___.
IGNOU ACADEMY
Your IGNOU journey, made easier.
  • Solved Assignments
  • Study Notes
  • Guess Papers
  • Question Papers
Skip in 10
Top
📞
Call Support Instant phone assistance IGNOU MST 21 2026 -  Two independent groups of patients were given Drug X and Drug Y. | IGNOU Academy
→
🟢
WhatsApp Chat Fast live messaging
→
Email Us Business enquiries & support
→