Introduction to Inferential Statistics for Educators H

a. A researcher measures the intelligence of college students who are first born in their families (n=25) compared to those who were born last in their families (n = 40).

b. The coach of your college football team conducts an informal survey showing that members of the team study an average of 3.5 hours per day. The coach makes the claim that this is equivalent to the amount of time students at the college study in general. You feel that the coach is incorrect. You randomly select 50 students from the college and ask them how much they study each day. Your result is that these 50 students study an average of 5.2 hours per day.

c. A researcher tests the memory scores of each of a group of 15 students twice, once while in a very noisy room and once while in a quiet room. She then compares the scores.

My friend answer it is not a correct None Given

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Question# 2

2. Describe a situation in which you would use a t test for dependent means that is not from an example in the text or lectures. Include the following information about your example

a. independent variable

b. dependent variable

c. null hypothesis

d. explain what you should do with the two scores obtained for each participant to conduct a dependent t-test hypothesis test

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For example: the difference between taking a math class in the morning and taking the same class afternoon for level of high school students

a- independent means: high school students.

b- dependent means: level of students in math class.

c- there are no difference between level of students who take the math class in morning or afternoon.

d- we should conduct them with theses differences.

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A. independent variable is the time of test: morning/afternoon B.  Dependent variable would be the score (which perhaps is what you mean by level) The high school students are your sample.

Question# 3

3. A research study evaluated elementary students’ vocabulary knowledge before and after a literary unit designed to have children learn vocabulary through works of fiction. The vocabulary tests given before and after the intervention were identical. The test had 20 questions and a score range of 0-20. Using the output, answer the following questions: 1. What is the null hypothesis of the study? 2. What are the independent and dependent variables? 3. Write up the results as they would be presented in an article. Be sure to include descriptive statistics, test statisitcs, p-value, and a one to two sentence summary of how the results can be interpreted.

My friend answer it is not a correct

1. The null hypothesis of the study is: There is no significant difference between elementry students’ vocabulary knowledge before and after a literary unit designed to have children learn vocabulary through works of fiction.

2. Independent variable: The literary unit. – Dependent variable: students’ vocabulary knowledge

3. Descriptive statistics: M = -1.875 , SD=

P= 0.451 P>.05 : There is no signifcant differne.

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2. The independent variable is the type of test (pre/post). The literary unit is the intervention.

3. The descriptive statistics report the mean difference score – it is important to specify what you are reporting. For the results you could have written the following: A comparison of pre and post vocabulary scores revealed statistically significant increases from pre to post test t(23) = -4.151, p<.001

Question#4

4. A researcher wanted to test the effectiveness of a new professional development initiative aimed at increasing teacher’s use of technology in the classroom.

At the beginning of the school year all teachers were told that using technology to improve instruction was a major district goal. 32 teachers from School A participated in a two-day intensive workshop focused on practical techniques for using technology to improve instruction; they were also given the informational packets about how to implement various instructional technology tools and the contact information for the technology and teaching specialist. 36 teachers in School B were given the informational packets about how to implement various instructional technology tools and the contact information for the technology and teaching specialist but received no training.

The two groups of teachers were then assessed by using a instructional technology integration index (a higher score indicates technology use is aligned with high quality instruction). The mean score on the index for teachers from School A was 8.9. The mean score for teachers from School B was 7.0

Do these results suggest that the intensive workshop had an impact on the technology integration index mean scores?

Indicate 

a. the type of test being conducted

b. show the five steps of the hypothesis test

c. write a one sentence summary of the study findings in non-statistical language (Use the .01 level.)

(You know that the estimated standard deviation of the distribution of differences between means  is SDIFFERENCE =.69)

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Step 2:  The comparison distribution is a t distribution with 66 df, mean=0, Sdifference = .69 Step 3:  The cutoff for a two-tailed test at .01 level with 66 df (rounded down to 65) is +/-2.654

Question# 5

5. A medical researcher is interested in determining whether a new medication for lung cancer is effective in a group of patients with early-stage disease. Explain what a Type I and Type II error would be in this study. ( Be sure to state your answer in terms of the variables of this particular study to get credit for your response .)