Evidence-Based Practice for Nurses

Match the following terms:

1. Range a. Rank


2. Semiquartile range b. Difference between maximum and minimum values


3. Percentile c. Measure of the average deviations of a value from the
   mean


4. Standard deviation d. Percentage comparing standard deviations when units
   of measure are different


5. z score e. Range of the middle 50% of data


6. Coefficient of variation f. Converted standard deviation to a standardized unit

TEST YOUR KNOWLEDGE 13-5

How did you do? 1. b; 2. e; 3. a; 4. c; 5. f; 6. d

13.6 Inferential Statistics: Can the Findings

Be Applied to the Population?

At the end of this section, you will be able to:

‹ Discuss the purpose of inferential statistical tests

‹ Explain how statistical testing is related to chance

When to Use Inferential Statistics

First, samples are analyzed using descriptive statistics. Then, if appropriate, in-

ferential statistical tests can be conducted to: (1) make decisions about whether

findings can be applied to the population, or in other words, to make inferences

about the population based on the sample, and (2) test hypotheses. For some stud-

ies, the use of inferential statistics is not appropriate, and their use depends on the

research questions being asked. Research questions that are descriptive would not

require inferential statistics. For example, the research question “How often do

nurses assess the use of herbal remedies by patients?” would best be answered by

using descriptive statistics, such as frequencies, means, and standard deviations.

Using parameter estimation to determine inferences to the population is

less common in nursing research; however, this approach is becoming more

popular with the emphasis on evidence-based practice (EBP) in nursing and

medicine (Borenstein, 1997; Straus, Richardson, Glasziou, & Haynes, 2010).

Most frequently, these estimates are reported as confidence intervals (CIs).

CIs are ranges established around means that estimate the probability of being

KEY TERM

confidence

intervals: Ranges

established

around means

that estimate the

probability of being

correct

352 CHAPTER 13 What Do the Quantitative Data Mean?