Textbook: Understanding Basic Statistics, 8th edition by Brase and Brase
Type your work in a WORD document. Please double-space. All problems should be in order.
1. Write a clear definition, in your own words, of the following terms. Give an example of each.
(a) Population
(b) Sample
(c) Variable
(d) Parameter
(e) Statistic
2. The dean of a community college wishes to estimate the average distance
students travel to school (in miles). He has a list of all the students
enrolled at the college this semester. A random sample of those students was
selected and those students chosen responded to a survey by stating the
distance they drive to school.
(a)
Describe the population.
(b) Describe the variable that is being
measured. Is it quantitative or qualitative?
(c) Describe the population parameter
the dean wants to estimate.
(d) Describe the sample.
(e) Describe the sample statistic that
will be calculated.
3. A business employs 205 workers. They would like to obtain a simple random
sample of 18 workers. Describe in words a process for how you would obtain this
sample. (General instructions here- not specific EXCEL or other technology
instructions.)
4.
Read the news article attached to this handout. Answer the following questions:
(a) Why was this study an experiment and
not an observational study?
(b) Describe the subjects.
(c) What question were the researchers
investigating?
(d) Describe in detail the design of
this experiment.
(e) Draw a picture that explains the
experimental design. (This should be similar to the one shown in Example 5 on
p. 24 of your textbook.)
(f) What were the results?
(g) Was there a control group,
randomization, blinding, and replication? For each of these principles discuss
how it was implemented, or why it could not be implemented.
5.
Identify each of the following samples by naming the sampling technique used
(cluster, convenience, simple random, stratified, systematic).
(a) A quality control manager selects every 8th computer chip that comes off the
assembly line.
(b) Southwest Airlines randomly selects
60 flights during a certain month and surveys all passengers on the flights.
(c) Shawn divides the day into four
parts: morning, midday, evening, and late night. He then measures his Internet
connection speed at 5 randomly selected times during each part of the day.
(d) A survey regarding download time on
a certain website is administered on the Internet to anyone who would like to
take it.
(e) Use a random number table to select
a sample of students enrolled at your college and then determine the number of
credit hours they have each accumulated toward their degree program.
Article for Question # 4: Pilot Study of Trigeminal Nerve Stimulation for ADHD
Currently approved in Canada and Europe for adults with medication-resistant depression and seizures, trigeminal nerve stimulation (TNS) has been found to be an effective and safe means of treatment for children with attention deficit hyperactivity disorder (ADHD), reports a study published in the April 2019 issue of the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP).
TNS utilizes a small stimulator worn on a child’s clothes to emit a low-level current, powered by a 9-volt battery. Thin wires are connected to the device with an adhesive electrode patch worn across the forehead during sleep. Mild stimulation to the skin, barely or not perceptible to the child, led to activation of deeper brain areas associated with concentration and impulse control. Children wore the patch an average of eight hours nightly and patches were removed each morning.
“ADHD is estimated to affect 9.5 percent of school-age children and 4.4 percent of adults,” said James McGough, MD, Professor and child psychiatrist at the Jane & Terry Semel Institute for Neuroscience and Human Behavior at University of California, Los Angeles, CA, USA. “Our current treatments mostly depend on medication with some role for behavioral therapies. Although there is great demand for non-medication ADHD treatments, the most popular options have minimal, if any, scientific evidence supporting their use.”
Investigators enrolled 62 children ages 8-12 years old and randomized them to receive active or sham TNS nightly for 4 weeks. Benefits in the active group were observed within the first week of treatment, with increasing improvement over the remaining weeks. Improvement compared with the sham group was demonstrated by the ADHD-Rating Scale (p = .005), the study’s primary outcome measure, and the Clinical Global Impression — Improvement scale (p = .003). The size of treatment improvement was similar to that seen with currently FDA-approved nonstimulant ADHD medications.
In addition to reductions in behavioral ADHD symptoms, investigators found positive changes in brain activation with active TNS, measured by electroencephalography (EEG). This finding, consistent with NIMH research priorities, emphasize measurable changes in neurological functioning in addition to behavioral improvement, suggesting that TNS has beneficial effects by increasing activity in brain circuits that modulate hyperactivity and impulsivity. Study results further suggested that TNS might be effective in reducing pediatric anxiety symptoms, consistent with other studies of TNS for adult depression and post-traumatic stress disorder.
A major limitation of many studies of non-medication ADHD treatments relates to difficulties maintaining effective blinding of the sham control condition. Investigators in this study demonstrated that after the initial week, parents of children in both active and sham TNS groups had equal expectation of benefit, suggesting that the study design successfully concealed which treatment children were receiving. This result, in addition to differences in brain activation measured by EEG, further supports the study’s conclusion regarding the potential of TNS for ADHD therapy.
“I am excited that we found significant reductions in ADHD symptoms, as well as associated improvements in brain functioning, as a result of TNS therapy,” added Dr. McGough, the lead author of the study. “Treatment was well accepted by patients and families, compliance was high, and there were no clinically important side effects. TNS has great potential as an additional option for managing ADHD.”
Journal Reference:
James J. McGough, Alexandra Sturm, Jennifer Cowen, Kelly Tung, Giulia C. Salgari, Andrew F. Leuchter, Ian A. Cook, Catherine A. Sugar, Sandra K. Loo. Double-Blind, Sham-Controlled, Pilot Study of Trigeminal Nerve Stimulation for ADHD. Journal of the American Academy of Child & Adolescent Psychiatry, 2019; DOI: 10.1016/j.jaac.2018.11.013
