24 Jan variability

Question 1

A nurse researcher in a large medical center is reviewing data from a study recently conducted on reducing the number of ventilator-associated pneumonia cases. She wants to obtain information on the spread of the data. This information will tell her how close or far apart the scores are from each other. This is known as

Variability

Power

Subject participation

Data cleaning

Question 2

A research article reports a limitation in the published study that the sample size was too low. How might this low sample size affect the study?

The study will not be affected by a low sample size.

The study will not be cost effective and resources will likely be wasted.

The study results may not be reliable and research questions may not be accurately answered.

The researcher will have to go back and include more participants in the study to increase the sample size which will delay completion of the study.

Question 3

As you read more closely into the study results, you see that the scores of the new nursing mothers are very far from the mean or average score. You think back on your research class and realize that that this means that the study scores have a large _______________.

range

standard deviation

variance

power

Question 4

Another study results show all of the scores in the center of the distribution curve. In other words, the average or mean scores are 50%. This means that the study has very little or limited (select all that apply)

Range

Skewness

Variability

Reliability

Question 5

You are talking to a nurse colleague who is proposing to conduct an innovative research study using warming blankets on patient pre-surgery to determine if post-operative complications are reduced. He tells you that he does not plan to perform a power analysis because he is including all patients scheduled for surgery over the next 6 months which will give him a sample size well over 4000 subjects. Which of the responses below is the most appropriate?

“Performing a power analysis helps to make sure that more subjects are not included than is necessary because excess resources may be used with little added benefit to the study.”

“That is great that you have such a high number of subjects, as the large number of subjects will increase the reliability of your study.”

“Too many subjects will decrease the reliability of the study, regardless of cost.”

“That is a good sample size, but did you get approval for subject payment to make sure there is enough money in the research budget?”

Question 6

A nurse colleague tells you that it is not important to perform a power analysis because he already knows that his sample size will be small in an upcoming study he is conducting on safety reporting on falls. The small sample size is already a known limitation. Which is the best response to the nurse?

“I see your point, the power analysis is used to determine sample size. It will be a waste of time and resources to perform the analysis since we already know the power will be limited.”

“The power analysis must be conducted regardless as mandated by state regulations.”

“While the power analysis does help determine sample size, it is helpful in determining the likelihood of your statistical test will be in detecting effects of that size in your particular situation.”

“If your sample size is that small, it will not be advantageous to conduct the research.”

Question 7

A nurse is discussing a recent research study with the hospital biostatistician. The study compared two groups of patients who received diagnostic breast biopsies to detect malignancy. One group received lavender aromatherapy and the other received jasmine aromatherapy. The hypothesis was that there would be a statistically significant difference in anxiety level between the two groups. More specifically, the assumption was that the lavender group would demonstrate a significant drop in anxiety level. He tells the biostatistician that he is concerned because the study results indicated that the null hypothesis turned out to be true. In fact, both groups showed a decrease in anxiety level despite the fragrance. What does this mean, and does the nurse have a reason for concern? Please select the best answer.

The nurse has a legitimate concern because the null hypothesis means that there was no difference between the groups. Since both groups’ anxiety level was decreased, the study is meaningless.

The nurse has a legitimate concern because the study was a waste of time and human and financial resources. The hospital will have to be reimbursed.

The nurse’s concern is unwarranted because just because the results were not as expected, important data were gathered and information about clinical practice was learned. The reason for research is to answer a question because although we may suspect the answer, we do not know.

The nurse does have a legitimate concern since the null hypothesis was correct and the study should be replicated with a larger sample size.

Question 8

You have been asked to present the four major measures of variability to your hospital research team, including: (choose all that apply)

range and interquartile range

skewness

variance

standard deviation

Question 9

The normal distribution curve depicts the distribution of all possible scores in a research study where the majority of the scores, or the mean or average scores would fall in the center of the curve. The closer the scores are to this midline means less

deviance

range

scores

variability

Question 10

You are reading a research article and you see that the scores fall primarily in the midline of the distribution curve. This curve is known as a

Normal distribution.

Skewed distribution.

Non-distribution.

Power distribution.