observe the efficiency of students to see whether students do better when they study all at once or in intervals. One group of 12 participants participated in the survey after studying for one hour continuously. The other group of 12

A First Course in Probability (10th Edition)
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Author:Sheldon Ross
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Chapter1: Combinatorial Analysis
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The university conducted a study to observe the efficiency of students to see whether students do better when they study all at once or in intervals.
One group of 12 participants participated in the survey after studying for one hour continuously.

The other group of 12 participated in the survey after studying for three twenty-minute sessions.

As per the survey, results group 1 had a mean score of 75 and a variance of 120.

Second group had a mean score of 86 and a variance of 100.

Assuming the normal populations, independent samples, and equal population variances conditions hold, are the mean test scores of these two groups significantly different at the 0.05 level?

Expert Solution
Step 1

The objective is to check whether the mean test scores of the two groups significantly differ at the 0.05 level.

Let Probability homework question answer, step 1, image 1 denote the  mean of the participants participated in the survey after studying for one hour continuously.

Let Probability homework question answer, step 1, image 2 denote the mean of the participants participated in the survey after studying for three twenty-minute sessions.

The null hypothesis is that there is no difference between the mean test of scores between the two groups. That is,

Probability homework question answer, step 1, image 3

The alternative hypothesis is that there is a difference between the mean test of the score between the two groups. That is,

Probability homework question answer, step 1, image 4

The level of significance is,

Probability homework question answer, step 1, image 5

 

Step 2

group 1:

Sample mean,Probability homework question answer, step 2, image 1

Sample variance,Probability homework question answer, step 2, image 2

Sample Size, n1=12

Group 2:

Sample mean,Probability homework question answer, step 2, image 3

Sample variance,Probability homework question answer, step 2, image 4

Sample size, n2=12

Given that the two variances are assumed to be equal, the test statistic is,

Probability homework question answer, step 2, image 5

The formula for pooled variance is,

 

Probability homework question answer, step 2, image 6

Step 3

The test statistic is computed below.

Probability homework question answer, step 3, image 1

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