Question

INTD 5064/OCCT 5023 - Applied Statistics for Health Care Practitioners
Magnets and Pain Relief Data Set
Magnet Treatment Group				Placebo Group
Subject	Before	After		Subject	Before	After
AM	10	10		LL	8	4
AA	10	4		LM	10	7
BC	8	7		MD	10	5
BR	10	0		MN	10	8
CM	10	4		JJ	9	8
FW	10	2		JA	10	6
GM	10	5		CR	9	8
GD	10	5		WT	10	10
HB	9	3		GJ	10	10
MG	10	10		BD	7	6
PD	9	2		EG	10	10
RW	10	2		RB	8	8
SF	10	3		DO	10	10
TS	10	4		DS	10	10
WA	10	10		NP	10	10
SH	8	4		GE	10	10
WK	10	3		DY	9	9
MR	10	0		KU	10	9
MS	8	2		UT	10	10
AR	8	7		AX	10	10
TN INTD 5064 – Applied Statistics for Health Care Practitioners t-test Homework For the items below, download the data set Magnets and Pain Relief Data Set. These data are a subset of data in a study by Vallbona, C., et al. Response of pain to static magnetic fields in postpolio patients: A double blind pilot study. Archives of Physical Medicine and Rehabilitation, (78), 1200-1203. In the original study, the researchers sought to answer the question “Can chronic pain experienced by postpolio patients be relieved by magnetic fields applied directly over an identified pain trigger point?” Subjects in the Treatment Group had a magnetic device applied to the site of pain for 45 minutes. Subjects in the Placebo Group had a non-magnetic device applied for 45 minutes. All subjects reported their pain before and after the experiment using a 0 to 10 scale (0 was the least pain, and 10 was the greatest pain). The data consist of self-report pain scores recorded before and after the experiment. This homework includes three opportunities to calculate obtained t values: 3.c., 5.e., and 7.b. Two of these items (3.c. and 5.e.) are highlighted. Choose one of the highlighted items to complete (3.c. OR 5.e.). All non-highlighted items are required (including 7.b.). What is/are the dependent variable(s) in the study? the independent variable(s)? Include the scales of measurement. Calculate appropriate measures of central tendency and variability for each variable you will need in this assignment, i.e., “before” and/or “after” pain scores for each group. Justify your choices. You may use Excel to calculate measures of central tendency and variability. A link has been provided for support in doing so. However, you may calculate those by hand or with a scientific calculator as well. The researchers anticipated that Magnet Treatment Group pain scores would be lower than Placebo Group pain scores at the end of the study. Write the null hypothesis, in prose and notation. (Pay close attention to the word “lower” in this exercise. Remember that lower scores indicate less pain and, thus, effectiveness of the magnets. What does this suggest for how the hypotheses are stated and for how the t distribution diagram is drawn?) a.Is the null hypothesis stated above one-tailed or two-tailed?Justify your answer. b.What type of test should be used to test the null hypothesis stated?Justify your answer.       c.Using the A-B-C-D format, test the null hypothesis. (Use ? = .05) The researchers wanted to know whether there was a difference in average pain levels for the Magnet Treatment Group and the Placebo Group at the beginning of the experiment. Why would it be reasonable and desirable to show that there were no differences? a.Write the null and alternate hypotheses, in prose and notation. b.Is the null hypothesis one-tailed or two-tailed?Justify your answer. c.What conclusions would you draw if the null hypothesis were rejected? d.What type of t test should be used to test the hypothesis?Justify your answer. Murphy, another investigator who had used another type of magnet, obtained patterns of results that resembled Vallbona’s results. After the experiment with 21 subjects, Murphy’s treatment group’s mean pain score was 5.50, and the standard deviation was 2.50. Murphy wished to test whether his “After” mean was greater than Vallbona’s “After” mean. Why would Murphy be interested in conducting this test? What information would this test provide? Without testing any formal hypotheses, what do the data suggest about differences between Murphy’s “After” mean and Valbona’s “After” mean? Justify your answer. Is the null hypothesis suggested above one-tailed or two-tailed? Justify your answer. What type of inferential test should Murphy use to test the hypothesis? Justify your answer. HINT: In this case, Murphy chose to use Vallbona’s mean as a hypothesized value. Using the A-B-C-D format demonstrated in class, test the null hypothesis that you stated in exercise 3d. (Use ? = .05) Think of a research question that would be appropriate for an independent-samples t-test. Share: The research question Hypotheses in prose and notation. The conclusion you would make if the null hypothesis were rejected. Complete a t-test using the data collected during the first week of class (i.e., the question you asked classmates). You can compare groups via gender or major, depending on your hypothesis. For example, as I mentioned, last year an MLS student asked his classmates how many times they had seen Star Wars. He hypothesized that there was a significant difference between MLS and DEHS students, so he compared those two groups. What type of inferential test should you use and why? Using the A-B-C-D format demonstrated in class, test the null hypothesis. (Use ? = .05)	10	4		PW	10	9

Answer 1

A.   What is/are the dependent variable(s) in the study? the independent variable(s)? Include the scales of measurement.

Dependent Variable: Pain scores before and after 0 to 10 scale (0 was the least pain, and 10 was the greatest pain) - Metric

Independent Variable: Type of treatment - Magnet and Placebo- Nominal

B.   Calculate appropriate measures of central tendency and variability for each variable you will need in this assignment, i.e., “before” and/or “after” pain scores for each group.  Justify your choices.

I have measures of central tendency and variability using excel.

EXCEL > DATA> DATA ANALYSIS TOOL PACK (ADDIn) > Descriptive Statistics

1. The researchers anticipated that Magnet Treatment Group pain scores would be lower than Placebo Group pain scores at the end of the study.  Write the null hypothesis, in prose and notation.  (Pay close attention to the word “lower” in this exercise. Remember that lower scores indicate less pain and, thus, effectiveness of the magnets. What does this suggest for how the hypotheses are stated and for how the t distribution diagram is drawn?)

a.    Is the null hypothesis stated above one-tailed or two-tailed?  Justify your answer.

Null Hypothesis = Magnet Treatment Group pain scores would be same as Placebo Group pain scores at the end of the study

Alternate Hypothesis: Magnet Treatment Group pain scores would be lower than Placebo Group pain scores at the end of the study