Chapter 16 Data Analysis Descriptive and Inferential Statistics

29. The change in heart rate in a group of patients was reported as 10.95 ± 9.21. A patient who had a change in heart rate score of 23 is how many SD from the mean? a. 1 SD b. 2 SD c. 3 SD d. 4 SD

ANS: A Correct A: 1 SD is correct; add 10.95 plus 1 SD (9.21), and the answer is 20.16; 23 is closest to 1 SD. Incorrect B: 1 SD is correct; add 10.95 plus 1 SD (9.21), and the answer is 20.16; 23 is closest to 1 SD. Incorrect C: 1 SD is correct; add 10.95 plus 1 SD (9.21), and the answer is 20.16; 23 is closest to 1 SD. Incorrect D: 1 SD is correct; add 10.95 plus 1 SD (9.21), and the answer is 20.16; 23 is closest to 1 SD

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 using a research study that involved categories of patient weights. The level of measurement that would be most appropriate in this study is what? 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'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 is using a nursing degree as a variable in a research study. The level of measurement most appropriate in this case is what? a. Nominal b. Ordinal c. Interval d. Ratio

ANS: A Correct A: This variable (type of nursing degree) is scaled using categorical data, nominal level. The type fits only one characteristic. Incorrect B: This variable (type of nursing degree) is scaled using categorical data, nominal level. The type fits only one characteristic. Incorrect C: This variable (type of nursing degree) is scaled using categorical data, nominal level. The type fits only one characteristic. Incorrect D: This variable (type of nursing degree) is scaled using categorical data, nominal level. The type fits only one characteristic.

Which data measurement scales typically use nonparametric tests of significance? (Select all that apply.) a. Nominal b. Ordinal c. Interval d. Ratio

ANS: A, B Correct A: Nonparametric tests of significance are used when data are measured on a nominal or ordinal scale. Correct B: Nonparametric tests of significance are used when data are measured on a nominal or ordinal scale. Incorrect C: Parametric statistics are used when data are scaled at the interval or ratio level scale. Incorrect D: Parametric statistics are used when data are scaled at the interval or ratio level scale.

5. Which statistical tests can have a range of correlation coefficients in values from -1.0 to +1.0? (Select all that apply.) a. Pearson product moment correlation coefficient b. Kendall's tau c. Spearman rho d. ANOVA

ANS: A, B, C Correct A: Correlation coefficients range in values from -1.0 to + 1.0. Correct B: Correlation coefficients range in values from -1.0 to + 1.0. Correct C: Correlation coefficients range in values from -1.0 to + 1.0. Incorrect D: This is a parametric statistical test that reports the F statistic that is not a range of values.

Which measures of central tendency allow for relative rankings? (Select all that apply.)a. Mode b. Range c. Median d. Mean e. Semiquartile range f. Percentile g. SD

ANS: A, C Correct A: The mode will allow for relative rankings. Correct C: The median will allow for relative rankings. Incorrect B: This is an ordinal measure of variability. Incorrect D: The mean will not allow for relative rankings. Incorrect E: This is an ordinal measure of variability. Incorrect F: This is an ordinal measure of variability. Incorrect G: This is an ordinal measure of variability.

Which measures of central tendency allow for rank ordering with equal intervals? (Select all that apply.) a. Mode b. Range c. Mediand. Mean e. Semiquartile range f. Percentile g. SD

ANS: A, C, D Correct A: The mode will allow for rank ordering with equal intervals. Correct C: The mode will allow for rank ordering with equal intervals. Correct D: The mode will allow for rank ordering with equal intervals. Incorrect B: This is an ordinal measure of variability. Incorrect E: This is an ordinal measure of variability. Incorrect F: This is an ordinal measure of variability. Incorrect G: This is an ordinal measure of variability.

3. Which parametric statistical test(s) compares the difference between mental status scores for patients with dementia (Group 1) and patients with confusion from dehydration (Group 2)? (Select all that apply.) a. The t test b. Pearson Product Moment Correlation Coefficient c. Chi-square d. Analysis of variance (ANOVA)

ANS: A, D Correct A: The t statistic tests where two group means are different; the dependent variable is mental status scores; there are two groups, dementia patients (Group 1) and dehydration patients (Group 2). Group is the independent variable. Correct D: ANOVA may be used to test whether the group means differ just as the t test does. Incorrect B: This test measures the association of two variables measured at ratio or interval levels; the example has an independent variable measured at nominal level and a dependent variable measured at interval or ratio level. Incorrect C: The chi-square statistic compares nominal level variables. Group is scaled at the nominal level, but mental status is not very likely scaled at interval level.

26. 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 8.6 b. Between 3.8 and 7.0 c. Between 3.8 and 5.4 d. Between 5.4 and 7.0

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.

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.

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

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.

Which term represents the most frequent score in a frequency distribution? a. Mean b. Mode c. Median d. Percentile

ANS: B Correct B: The category with the highest frequency is the mode and is used often with nominal-level data. Incorrect A: The mean as an average represents interval- and ratio-level data. Incorrect C: The median is the middle score or the score when 50% of the scores are above it and 50% of the scores are below it. Incorrect D: Percentile represents the percentage of cases a given score exceeds.

A nurse researcher would opt to use factor analysis in which case? a. To control statistically for a variable and measure differences among group means b. To take a large number of variables and group them into a smaller number of factors c. To test the relationship between two variables measured at interval or ratio level data 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.

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 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.

8. Which measures of variability allow for rank ordering with equal intervals? (Select all that apply.) a. Mode b. Range c. Median d. Mean e. Semiquartile range f. Percentile g. SD

ANS: B, E, F, G Correct B: The range will allow for rank ordering with equal intervals. Correct E: The semiquartile range will allow for rank ordering with equal intervals. Correct F: The percentile will allow for rank ordering with equal intervals. Correct G: The SD will allow for rank ordering with equal intervals. Incorrect A: The mode is a measure of central tendency. Incorrect C: The median is a measure of central tendency. Incorrect D: The mean is a measure of central tendency.

​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 nurse researcher is interested in using nominal level data. The object or event that could be used if nominal-level data are of primary interest is what? a. Test scores b. Education level c. Marital status d. Weight

ANS: C Correct C: Marital status is most often represented by nominal-level data. Incorrect A: Test scores are best represented by interval-level data. Incorrect B: Education level is best represented by ordinal data: increasing rankings of education level. Incorrect D: Weight is represented by interval or ratio-level data

28. 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 b. Low c. Moderate d. High

ANS: C Correct C: The example can be described as a moderately strong correlation that is statistically significant. Incorrect A: The example can be described as a moderately strong correlation that is statistically significant. Incorrect B: The example can be described as a moderately strong correlation that is statistically significant. Incorrect D: The example can be described as a moderately strong correlation that is statistically significant.

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. Incorrect D: The semiquartile range is more stable than the range; it is less likely to be changed by a single extreme score.

The nurse researcher finds that the data include a score reported to be in the 75th percentile. The researcher interprets this to mean what? a. The score is at the median. b. The score has exceeded the 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 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 than quantitative.

ANS: C Correct C: This is characteristic of ratio measurement. Incorrect A: This response is true for all levels of data: nominal, ordinal, interval, ratio Incorrect B: This is true for intervals between numbers for interval- and ratio-level data. Incorrect D: This response does not describe interval-level data.

16. What conclusion can be drawn from statistics that indicate the mean nursing salary in a specific city is $55,000, the range is $38,000 to $78,000, the median salary is $58,000, and the mode is $56,000? a. The standard deviation (SD) is small. b. The mode can be calculated from the median. c. The average nursing salary in this city is $55,000. d. The mean does not reflect the true salary for nurses in this city.

ANS: C Correct C: This is the average or mean nursing salary. 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.

​Which characteristic is an essential criterion for categorizing an object, event, or fact as nominal level data? (Select all that apply.) a. The degree of the characteristic must be positively related to the number assigned. b. Rank orders must be calculated for meaningful interpretation. c. Categories must be mutually exclusive. d. Category ranges cannot overlap

ANS: C, D Correct C: This is the definition of nominal-level data; categories are mutually exclusive. Correct D: Category ranges must not overlap; each score fits into only one category. Incorrect A: This answer does not fit categorizing an object, event, or fact as nominal level. Incorrect B: Rank orders apply to ordinal-level data, not to nominal-level data.

Which statements regarding measures of central tendency are accurate? (Select all that apply.) a. This classification of levels of measurement is scientifically inaccurate. b. Having the mean, mode, and median exactly the same indicates the measures have been correctly applied. c. They have great flexibility with regard to the amount of mathematical manipulation possible. d. They vary from sample to sample,even when the same trait or characteristic is measured.

ANS: C, D Correct C: Various inferential statistical tests employ mean, median, or mode in their calculations. Correct D: Measures of central tendency vary from sample to sample, even when the same trait is measured. Incorrect A: The classification of levels of measurement is well accepted by the scientific community. Incorrect B: This is an inaccurate statement.

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.

A nurse researcher would opt to use measures of central tendency in which case? a. When there is a need to describe how reliably the findings can be generalized b. When there is a need to describe how much dispersion is in the sample c. When there is a need to describe the accuracy of predictions made d. When there is a need to describe the average member of the sample

ANS: D Correct D: Measures of central tendency yield a single number that describes the middle of the group and summarizes the members of a sample. Incorrect A: This answer describes a function of inferential statistics. Incorrect B: This answer describes measures of variability. Incorrect C: This answer is incorrect.

27. 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

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 d. Ratio

ANS: D Correct D: Ratio measurement is the highest level of measurement; all mathematical procedures can be performed on data from ratio scales. Incorrect A: Nominal-level data allow the least amount of mathematical manipulation. Incorrect B: Ordinal-level data are limited in the amount of mathematical manipulation possible. Incorrect C: Interval-level data allow for a great amount of data manipulation.

​The nurse researcher is using respiratory rate as a variable in a research study. The level of measurement most appropriate in this case is what? a. Nominal 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.

22. 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.

The nurse researcher is interested in describing the assignment of numbers to objects or events. This is best achieved in which way? a. Through use of prediction 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.

20. In a study of women's adjustment to breast cancer, the youngest participant was 23 years old and the oldest participant was 89 years old. How should the nurse researcher interpret this data? a. This is the mean age. b. This is the modal age. c. This is the median age. d. This is the range in age.

ANS: D Correct D: This example illustrates a measure of dispersion or variability, the difference between the highest and lowest scores. Incorrect A: This example does not illustrate an average. Incorrect B: This example does not reflect the average represented by the category with the highest frequency. Incorrect C: This example does not reflect the average represented by the point at which 50% of the scores fall above and 50% fall below

The alpha level that is interpreted by the nurse researcher as a highly statistically significant result is what? a. p = 0.20 b. p = 0.02 c. p = 0.002 d. p = 0.0002

ANS: D Correct D: This is the most highly statistically significant result. Incorrect A: This result is above the conventional 0.05 and is not statistically significant. Incorrect B: Although this result is statistically significant, it is not highly statistically significant. Incorrect C: This is a highly statistically significant result, but not the highest.