A teacher gives a 3 rd grade class ( n = 40) a math test at the beginning of the

Question

A teacher gives a 3rd grade class (n = 40) a math test at the beginning of the semester. To assess the effectiveness of the teacher’s instruction, the students are tested again at the end of the year. What statistical test is appropriate to determine if there has been a significant change (effective teaching from the beginning of the school year to the end of the school year?

1. What is the appropriate test to use? _____________________

2. State the Null Hypothesis: ____________________________

3. One or Two-Tailed Test: ______________________________

After

reading several published journal articles about how a new leadership training

program increases a company’s profits, a CEO hires a researcher to replicate

the findings at his own company. The researcher randomly assigns half of

the company managers to receive the training while the other half does not

receive the training.

1. What is the appropriate test to use:

__________________________

2. State the Null

Hypothesis: _________________________________

3. One or two-tailed test: ____________________________________

On one

standardized measure of IQ the population mean is 100 and the standard

deviation is 15. Imagine that you want to test the hypothesis that

children in private schools have an average IQ that is different than the national

average. You randomly select a sample of 100 students from private schools

and the mean is 110.

1. What is the appropriate test to use?:

__________________________

2. State the Null

Hypothesis: ___________________________________

3. One or Two-Tailed Test: _____________________________

1.      A researcher hypothesizes that undergraduate college students eat fast food more often than graduate students. The researcher selects two random samples (one of undergraduate students and one of graduate students) and has them report how many times they have eaten fast food in the past week. Given the following information, determine the proper conclusion for the researcher.

Undergraduate Students

Graduate Students

(x = 8)    for undergraduates

2

4

((x-M)2 = 5.2) for undergraduates

3

3

2

6

(x = 28)    for graduates

0

7

((x-M)2 = 13.34) for graduates

1

3

-

5

1. Appropriate test to use:   _________________________________ (3 points)

2. What is your alpha level set to?    = ___________ (3 points)

3. Calculate your degrees of freedom:  df = __________________ (4 points)

4. One or two-tailed test?    ____________ (3 points) 5. Determine the critical value(s) (tcrit) = ___________ (3 points)   

6. Results in Correct Form: _________________________________ (4 points)

A researcher involved in politics is interested in determining the extent to which a television advertisement will improve peoples’ attitude toward a candidate. To test this, the researcher administers a questionnaire to participants (n = 4) to measure their attitude toward the candidate one month before and one month after they view the advertisement. Their attitude responses are in the data below. A low score indicates a negative attitude towards the candidate and a high score indicates a positive attitude. Given that the standard deviation of the difference scores was found to be equal to 2.94 and the standard error of the difference was found to be equal to 1.47, determine the proper conclusion for the researcher.

Be sure to complete the problem (analyze the data!), and then answer the questions below.

Questionnaire

(Before Viewing)

Questionnaire

(After Viewing)

S1

5

5

S2

2

4

S3

3

10

S4

2

5

1. Appropriate test to use:  _________________________________  (5 points)

2. Results in Correct Form: _________________________________ (5 points)

3. Calculate a 95% Confidence Interval:________________________ (5 points)

4. Calculate Effect size: ____________________________________(5 points)

Undergraduate Students

Graduate Students

(x = 8)    for undergraduates

2

4

((x-M)2 = 5.2) for undergraduates

3

3

2

6

(x = 28)    for graduates

0

7

((x-M)2 = 13.34) for graduates

1

3

-

5

Explanation / Answer

Teacher - Student
(1) It is appropriate to use t-test for dependent samples

(2)
Here mu1 stands for the mean before and mu2 stands for the mean after
Null hypothesis, H0: mu1 - mu2 >= 0
Alternate Hypo, H1: mu1 - mu2 < 0

(3)
This is left tailed test i.e. one tailed.

CEO question
(1) It is appropriate to use t-test for independent sample with different variances

(2)
Here mu1 stands for the mean of company mangers who received training and mu2 stands for the mean of company managers who did not receive any training.
null hypo: H0: mu1 - mu2 <= 0
alternate: H1: mu1 - mu2 > 0

(3)
This is right tailed test i.e. one tailed

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