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The following information was obtained from matched samples taken from two populations. Assume the population of differences is normally distributed.

Individual :1 2 3 4 5;
Method 1: 7 5 6 7 5 ;
Method 2: 5 9 8 7 6.

The null hypothesis tested is H0: μd = 0. The test statistic for the difference between the two population means is:________

a. 0.
b. 2.
c. -2.
d. -1

Answer :

Answer:

Correct option is d. -1.

Step-by-step explanation:

The dependent t-test (also known as the paired t-test or paired samples t-test) compares the two means associated groups to conclude if there is a statistically significant difference amid these two means.

The hypothesis for the test can be defined as follows:

[tex]\text{H}_{0}:\mu_{d}=0\ \text{vs.}\ \text{H}_{\alpha}:\mu_{d}\neq0[/tex]

The test is given by:

[tex]t=\frac{\bar d}{S_{d}/\sqrt{n}}[/tex]

Compute the differences as follows:

Individual       Method 1       Method 2       Difference (d = 1 - 2)

      1                      7                    5                        2

      2                     5                    9                       -4

      3                     6                    8                       -2

      4                     7                    7                         0

      5                     5                   6                         -1

Compute the sample mean and sample standard deviation of the differences as follows:

[tex]\bar d=\frac{1}{n}\sum d=\frac{1}{5}\times [2-4-2+0-1]=-1\\\\S_{d}=\sqrt{\frac{1}{n-1}\sum (d-\bar d)^{2}}=\sqrt{\frac{1}{4}\times20}=2.2361[/tex]

Compute the test statistic as follows:

[tex]t=\frac{\bar d}{S_{d}/\sqrt{n}}[/tex]

  [tex]=\frac{-1}{2.2361/\sqrt{5}}\\\\=-1[/tex]

Thus, the test statistic for the difference between the two population means is -1.

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