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Chapter 16 Data Analysis Descriptive
and Inferential Statistics
The nurse researcher is interested in estimating how reliably data can be used to generalize the findings of a study. In order for this to occur, the researcher should use what? a. Inferential statistics b. Descriptive statistics c. Nonparametric statistics d. Mathematical statistics ANS: A Correct A: Inferential statistics are used by researchers to make predictions and generalize findings based on data. Incorrect B: Descriptive statistics are used to describe and summarize data by reducing data to manageable proportions by summarizing them. Incorrect C: Nonparametric statistics are a type of inferential statistics. Incorrect D: The term mathematical statistics is a circular answer.
The nurse researcher is interested in describing and summarizing the characteristics of the sample used in the research study. In order for this to occur, the researcher should use what? a. Inferential statistics b. Descriptive statistics c. Nonparametric statistics d. Mathematical statistics ANS: B Correct B: Descriptive statistics are used to describe and summarize data by reducing data to manageable proportions by summarizing them. Incorrect A: Inferential statistics are used by researchers to make predictions and generalize findings based on data. Incorrect C: Nonparametric statistics are a type of inferential statistics. Incorrect D: The term mathematical statistics is a circular answer. A nurse researcher would opt to use measures of central tendency in which case? a. When there is a need to describe
b. Through use of dispersion c. Through use of variability d. Through use of measurement ANS: D Correct D: This answer fits the definition provided in the stem. Incorrect A: This answer does not fit the definition provided in the stem. Incorrect B: This answer represents a measure of variability description. Incorrect C: This answer represents a measure of dispersion (variability) description. A nurse researcher determines the assignment of a number to an object for measurement by verifying what? a. The objects vary within a narrow range to meet category requirements. b. All objects assigned a specific measurement number are similar to all other objects assigned the same number. c. The objects assigned to one
specific number are positively related to the dependent variable of the study. d. The objects assigned to one specific number are positivelyrelated to the independent variable of the study. ANS: B Correct B: The assignment of a number or a value to a category that represents the category must be consistently applied to similar objects assigned the same number- value label. Incorrect A: A narrow range is not necessary to meet category requirements; the range may be large. Incorrect C: The numbers assigned to objects are consistently applied; this relates to independent and dependent variables. Incorrect D: The numbers assigned to objects are consistently applied; this relates to independent and dependent variables. The nurse researcher is interested in having the greatest flexibility possible in choosing statistical procedures. The level of measurement used to achieve this is what? a. Nominal b. Ordinal c. Interval
a. Nominal b. Ordinal c. Interval d. Ratio ANS: A Correct A: The data are represented by nominal-level data, categories, or classifications. Incorrect B: The data are represented by nominal-level data, categories, or classifications. Incorrect C: The data are represented by nominal-level data, categories, or classifications. Incorrect D: The data are represented by nominal-level data, categories, or classifications. The nurse researcher opts to use interval-level data. The researcher's primary concern will be what? a. Categories must be mutually exclusive. b. Intervals between data categories must be equal. c. The rank of zero (0) represents the absence of the measured variable. d. Variance between assigned
categories is qualitative rather than quantitative. ANS: B Correct B: This is the defining characteristic of interval measurement. Incorrect A: This response is true for all levels of data: nominal, ordinal, interval, ratio. Incorrect C: The zero does not represent the total absence of a variable in interval- level data. Incorrect D: This response does not describe interval-level data The nurse researcher opts to use ratio-level data. The researcher's primary concern will be what? a. Categories must be mutually exclusive. b. Intervals between data categories must be equal. c. The rank of zero (0) represents the absence of the measured variable. d. Variance between assigned categories is qualitative rather
b. Ordinal c. Interval d. Ratio ANS: D Correct D: Respiratory rate can have an absolute zero—absence of respirations. Incorrect A: Rate is represented by a number representing frequency per minute. Incorrect B: Rate is represented by a number representing frequency per minute. Incorrect C: Rate is represented by a number representing frequency per minute. The nurse researcher is using the percentage of nurses holding various nursing degrees as a variable in a research study. Which type of statistics is most appropriate in this case? a. Inferential statistics b. Descriptive statistics c. Nonparametric statistics d. Mathematical statistics ANS: B Correct B: Percentage represents descriptive statistics. Incorrect A: Percentage represents descriptive statistics. Incorrect C: Nonparametric statistics are used when testing hypotheses on data generated at nominal and ordinal units.
Incorrect D: This is a circular answer and does not apply The nurse researcher opts to group frequency data using large interval widths in a research study. Which problem may be encountered by using this type of interval widths? a. Overlap can occur. b. Patterns can be obscured. c. Means cannot be determined. d. Some data may not fit into any category. ANS: B Correct B: Very large interval widths lead to loss of data information and may obscure patterns in the data. Incorrect A: Overlap is eliminated by defining the size of the group or interval width so that no score falls into two groups. Incorrect C: Frequency intervals do not generate means. Incorrect D: Data or a score generated on a variable will fit into one frequency interval defined by the investigator. Which term represents the most frequent score in a frequency distribution? a. Mean
Incorrect A: The SD is most likely large. Incorrect B: The mode is the category or grouping with the highest frequency. Incorrect D: The mean is an average; it is more stable than the mode or median and is most likely closest to the true nursing salary in the neighborhood. The nurse researcher's data contain extremes of high and low scores. The measure of central tendency that should be used in order to be least affected by extremes of high and low scores is what? a. Mean b. Mode c. Median d. Percentile ANS: A Correct A: The mean is affected by every score and the least affected by chance. The larger the sample size, the less affected the mean will be by a single score. The mean is the most stable, least affected by extremes, and most useful for other calculations. Incorrect B: The mode is unstable and can fluctuate widely from sample to sample from the same population. Incorrect C: The median is not sensitive to extremes in high and low scores; it is less stable than the mean. Incorrect D: Percentile is not a measure of central tendency; the median is the 50th percentile. The nurse researcher should report the mean, mode, and median of a variable in a research study in which case? a. When the distribution is uneven.
b. When the distribution is wide. c. When the distribution is narrow. d. When the distribution is symmetrical. ANS: D Correct D: If the distribution of a variable of a sample is symmetrical and unimodal, the mean, mode, and median should be reported. Incorrect A: This is an inaccurate statement. Incorrect B: This is an inaccurate statement. Incorrect C: This is an inaccurate statement. The nurse researcher opts to use a measure of variability. Which measure of variability does the researcher recognize as being most unstable? a. Mean b. Median c. Range d. Semiquartile range ANS: C Correct C: The range is very likely to be changed by a single extreme score. Incorrect A: Mean is a measure of central tendency. Incorrect B: Median is a measure of central tendency.
mode. c. The score is exceeded by only 25% of the cases. d. The score represents the average of all scores measured at this time. ANS: C Correct C: The score of 75% is exceeded by only 25% of the cases. Incorrect A: You cannot conclude this based on the data provided. Incorrect B: You cannot conclude this based on the data provided. Incorrect D: This is not a logical answer.
- The nurse researcher determines that a correlation exists between two variables. How should the researcher interpret this information? a. The correlation describes the most frequently occurring score. b. The correlation describes the variability of scores from the mean. c. The correlation describes the range of the middle 50% of the scores. d. The correlation describes the magnitude and direction of the relationship between variables. ANS: D Correct D: This answer defines correlation.
Incorrect A: This answer defines mode. Incorrect B: This answer describes a measure of dispersion or variability. Incorrect C: This describes the semiquartile range. In a study of nurses' willingness to care for patients with a contagious disease, it was found that the greater the nurses' spirituality, the greater the willingness to provide care. This finding represents what? a. No correlation b. Perfect correlation c. Positive correlation d. Negative correlation ANS: C Correct C: Both of the variables are correlated in the same (+, +) direction. Incorrect A: The example suggests a correlation, not the absence of a correlation. Incorrect B: There is no indication in the example of a 1.0 correlation coefficient. Incorrect D: The variables are not correlated in opposite (+, -) directions. The alpha level that is interpreted by the nurse researcher as a highly statistically significant result is what? a. p = 0. b. p = 0. c. p = 0. d. p = 0.
d. To measure the relationship between one outcome or dependent variable and several dependent variables ANS: B Correct B: This is a definition of factor analysis. Incorrect A: This answer defines analysis of covariance. Incorrect B: This defines a correlation coefficient. Incorrect D: This answer defines multiple regression.
- A measure of anxiety produced a mean score of 5.4 with an SD of 1.6. Where would 68% of the scores fall? a. Between 2.2 and 8. b. Between 3.8 and 7. c. Between 3.8 and 5. d. Between 5.4 and 7. ANS: B Correct B: 68% of the scores would fall here. Incorrect A: 95% of the scores would fall here.
Incorrect C: This range is -1 (3.8) to the mean (5.4) on the curve. Incorrect D: This range is from the mean (5.4) to +1 (7.0) on the curve.
- What could a nurse researcher conclude about a variable of nominal level data that shows a high modal percentage? a. Increased variability; homogeneous sample b. Increased variability; heterogeneous sample c. Decreased variability; homogeneous sample d. Decreased variability; heterogeneous sample ANS: D Correct D: Nominal-level measurement categorizes a sample of variables such as gender. If you have a sample of 100 subjects, where 90 (90%) are female and 10 (10%) are male, the 90% modal category of female indicates one of decreased variability, homogeneous sample. Incorrect A: The example describes decreased variability, homogeneous sample. Incorrect B: The example describes decreased variability, homogeneous sample. Incorrect C: The example describes decreased variability, homogeneous sample
- An instrument produced a correlation coefficient: r = 0.49, p = 0.04. How would a nurse researcher interpret the magnitude of this correlation? a. Very low
