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Independent Sample Testing of Hypothesis

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A researcher conducts an independent-measures study comparing two treatments and reports the t statistics as t(25)= 2.071.
How many individuals participated in the entire study?
use a two tailed test with o=.05 and the distributions tool below to determine if there is significant difference between the two treatments.
t-critical=_ ______
* Reject the null hypothesis; there is no significant difference
* Fail to reject the null hypotheses; there is no significant difference.
* Reject the null hypothesis, there is a significant difference
* Fail to reject the null hypothesis; there is a significant difference.

Compute r2 to measure the percentage of variance accounted for by the treatment effect.
* 14.6%
*7.1%
* 7.6%
*13.6%

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Answers:
The number of individuals participated in the entire study = 27
t-critical= +/- 2.060
Reject the null hypothesis, there is a significant difference
r2 = 14.6%

Explanations:
Here, the degrees of freedom of the test is given to be 25.
For an ...

Solution Summary

The solution explains the determination of sample size, critical value and percentage of variance accounted for by the treatment effect for a independent sample t test.

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Statistics Problems: Test for mean, proportion, paired samples, independence

See attached file for clarity of the tables included.

1. ONE SAMPLE HYPOTHESIS TEST FOR MEAN: A bowler who has averaged 196 pins in the past year is asked to experiment with a ball made of a new kind of material. If he rolls 25 games with the new ball, averaging 204 pins with a standard deviation of 24.9, can one conclude at a level of significance of .01 that the new ball has improved his game?
1a) Direction = UPPER TAILED / LOWER TAILED / 2-TAILED (circle one)
1b) P-value = ________________
1c) REJECT THE NULL or DO NOT REJECT THE NULL? (circle one)
1d) Can we conclude the ball improved his game? YES or NO (circle one)

2. ONE SAMPLE HYPOTHESIS TEST FOR PROPORTION: The Trinity University librarian believes that more than 60% of the books checked out by students was fictional material. In a random sample of 1000 students who checked books out in the last year, 628 checked out fictional material. What can one conclude about the librarian's hypothesis at a level of significance of .05?
2a) Direction = UPPER TAILED / LOWER TAILED / 2-TAILED (circle one)
2b) P-value = ________________
2c) REJECT THE NULL or DO NOT REJECT THE NULL? (circle one)
2d) Can we conclude the librarian's claim is correct? YES or NO (circle one)

3. TWO SAMPLE HYPOTHESIS TEST FOR MEAN - INDEPENDENT SAMPLES: Eight college students were randomly divided into 2 groups of 4 each to test whether background music reduces studying capacity. Each person was tasked with memorizing a list of 20 words. Group 1 had music playing through earphones they were wearing. Group 2 was not distracted. The following are the number of words correctly remembered by each subject. Test whether the music reduces studying capacity at a .05 level of significance.

Group 1 -- DISTRACTED Group 2 - NOT DISTRACTED
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3a) Direction = UPPER TAILED / LOWER TAILED / 2-TAILED (circle one)
3b) P-value = ________________
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Group 1 -- BEFORE Group 2 - AFTER
Woman #1
Woman #2
Woman #3
Woman #4 134
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