Page 283 - DMGT404 RESEARCH_METHODOLOGY

Unit 12: Hypothesis Testing

 Identify a test statistic that can be used to assess the truth of the null hypothesis. Notes
 Compute the P-value, which is the probability that a test statistic at least as significant as
the one observed would be obtained assuming that the null hypothesis were true.
 The smaller the r -value, the stronger the evidence against the null hypothesis.

 Compare the r -value to an acceptable significance value .
 If p £  , that the observed effect is statistically significant, the null hypothesis is ruled out,
and the alternative hypothesis is valid.

12.8 Keywords

Alternate Hypothesis: An alternative hypothesis is one that specifies that the null hypothesis is
not true. The alternative hypothesis is false when the null hypothesis is true, and true when the
null hypothesis is false.
ANOVA: It is a statistical technique used to test the equality of three or more sample means.

Degree of Freedom: It is the consideration that tells the researcher the number of elements that
can be chosen freely.
Null Hypothesis: The null hypothesis is a hypothesis which the researcher tries to disprove,
reject or nullify.
Significance Level: Significance level is the criterion used for rejecting the null hypothesis.

12.9 Review Questions

1. What hypothesis, test and procedure would you use when an automobile company has
manufacturing facility at two different geographical locations? Each location manufactures
two-wheelers of a different model. The customer wants to know if the mileage given by
both the models is the same or not. Samples of 45 numbers may be taken for this purpose.
2. What hypothesis, test and procedure would you use when a company has 22 sales
executives? They underwent a training programme. The test must evaluate whether the
sales performance is unchanged or improved after the training programme.
3. What hypothesis, test and procedure would you use in A company has three categories of
managers:
(a) With professional qualifications but without work experience.
(b) With professional qualifications accompanied by work experience.

(c) Without professional qualifications but with work experience.
4. Each person in a random sample of 50 was asked to state his/her sex and preferred colour.
The resulting frequencies are shown below.

Red Blue Green
Colour
Male 5 14 6
Sex Female 15 6 4

A chi-square test is used to test the null hypothesis that sex and preferred colour are
independent. Will you reject at the null hypothesis 0.005 level? Why/Why not?

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