Statistics Final
What are Misleading Reported Statistics Descriptors?
-Reporting some but not all, limits understanding of data set -Reflects the overall data set, may not speak to individuals
What is a Dependent variable?
The variable that is being predicted or explained
What is Descriptive Statistics?
statistics that describe a collection of data i.e. number of people ages 75+ with the Rona
What is Inferential Statistics?
statistics that has an Ability to predict something i.e. why individuals over age 75+ are COVID-19 +
What is the formula for Variance?
sum of individual scores minus the mean squared divided by N minus 1
What are measures of central tendency?
summary of statistic (number) that represents center point of typical value of dataset [mean, mode, median]
What is Variance?
the average of the squared deviations from the mean -Commonly used statistic to measure dispersion or variability, but it is in terms of squared units
What is Grouped Frequency?
they simplify a frequency distribution for a variable that contains a large number of categories Combine some or all of the categories into a smaller number of meaningful groupings
What are some advantages of using the Median?
unaffected by extreme scores Gives more information about the entire set of data than does the mode
How do we understand potentially thousands (millions of numbers in data set?
use statistical analysis program like SPSS
Quiz 1 question: Using statistics to support practice decisions is unethical.
o False x true
What is Non-probability Sampling?
- Although less desired, it remains a very useful technique - Convenience or availability sample - Typically, cannot randomly select who our service recipients will be - Rather must rely on who can be available
What are the types of measurement methods?
-Direct Observation -Self-report -Questionnaires, Scales - Examining available work
These are reasons why we should study statistics
-It makes me better able to help people - more compassionate practitioner -a part of my ethical practice skills - an expertise of practice appraisal and establishes my best practices -part of my evidence-based practice application -useful at all levels of my profession (clinical, administration/planning, community organizing, social action, etc.) -keep from being misled -Empowers me to marshal data in support of my position (ethically of course) -It helps me ensure the effectiveness of my work with clients and units, and to adjust it quickly and appropriately
This is an example of a Grouped Frequency
0 = (1 to 2), 2 = (2 to 5), 3 = (6 to 10), 4 = (11 or more)
How to get Frequency percentage?
1) Each category as percentage of total N 2) Frequency ÷ total frequency in the set x 100 = % i.e. 2 ÷ 50 = .04 x 100 = 4 or 4% of the variable
What is the most common Cross-Tabulation table?
2x2 table
What is a Frequency Distribution?
A list of the frequencies for each category of a variable. They provide a sense of the overall nature of you data.
What is Standard Deviation?
A measure that reflects how far the values range from the mean value. -Used with interval and ratio data -Positive square root of the variance -We often use the standard deviation to estimate how many scores fall above or below the mean
What is a variable?
A property of objects that can take on different values
What is a Control variable?
A variable that is held constant in order to assess or clarify the relationship between two other variables
What do Inferential statistics allow us to do?
Allow us to determine probability that any given result can be attributed to chance (sampling error) Can make generalizations about populations Allows us to make predictions -Mostly grouped together as parametric and Based on normal distributions and higher levels of measurement
What are advantages of using the Mean?
Can be manipulated algebraically Relatively stable across samples
What are the characteristics of a Bar Graph?
Depicts frequency distributions, using vertical bars to show the number of percentage of cases for each category. -Used with nominal data -Bars do not touch each other or overlap -For every category there is an equally wide bar
What are measures of dispersion/variability?
Describing how spread out set of data is [range, interquartile range, standard deviation]
What is Cumulative Frequency?
Displays how absolute and relative frequency distributions add up as one observes from one category to the next of the variable displayed
What is a benefit of probability sampling?
Ensures that researchers'/clinicians' biases, limited knowledge, or errors, etc, do not influence the process.
What is an Interval level of measurement
Equal intervals -Specific amount of more or less of the variable -Differences precisely known -Does not have an absolute zero point -Examples: Fahrenheit and Celsius temperature scales; IQ score
What is a Ratio level of measurement?
Equal intervals w/absolute zero point -Differences precisely known -Ratios are legitimate -Can use mathematical operations -Examples: Age, weight, distance
What is a Boxplot?
Graph Illustrates median, range, interquartile range It will also display outliers Use for interval or ratio level variables
What is a Range?
How much do individual values/scores vary around the mean? -Measure of distance from the lowest to the highest score -Maximum number subtract minimum number= Range -Often used to show fluctuation between scores -Can be distorted by outliers 3, 3, 7, 7, 8, 8, 8, 9, 12, 12, 15 15-3=12 the range is 12
What are some questions to ask about the Measures of Dispersion?
How much do individual values/scores vary around the mean? How spread out are the values/scores in a data set? Is it a tight shot group or a loose shot group? What is the dispersion pattern of values?
What is an Intervening variable?
Hypothetical variable used to explain causal links between other variables
What are characteristics of EBP?
Integrating the best available research evidence, practice expertise, and client attribute
What are some disadvantages of using the Median?
It isn't very stable across samples It can't be manipulated algebraically
What is a Mode?
Most commonly occurring score (frequency)/or the number appearing most frequently in a distribution -Nominal, ordinal or metric variables -Easiest measure, no calculations necessary
What are some disadvantages of using the Mean?
May not represent a real value i.e. Mean age of 41 but no one is 41 Affected by extreme scores
What is Validity?
Measures are validity when they truly and accurately measure what they intend to measure
What types of measures are in descriptive statistics?
Measures of central tendency Measures of dispersion/variability
What are some disadvantages of using the Mode?
Not very representative of the entire set of data Affected by grouping or rounding of the data May be more than one mode (bimodal, multimodal distribution of scores)
What are the characteristics of Evidence-Based Practice?
Practitioner's expertise Best research evidence Client attributes
What is Relative Frequency?
Proportions or percentages of cases per category
What is a Meta-analysis?
Quantitative, formal, study design used to systematically assess the results of previous research to derive conclusions about that body of research A Systematic review of existing studies which aggregates their statistical results
What is an Inter-Quartile Range?
Range of middle 50% of scores -Typically eliminate upper and lower 25% of scores to control for outliers -Discards 50% of the data -Any justifiable percent can be used, but then it is not called an inter-quartile range
What is an Ordinal level of measurement?
Rank ordered -Relatively ranked, more or less of the variable -Don't precisely know differences -Examples: College Football team rankings
What are some advantages of using the Mode?
Represents the largest number of scores Applicable to nominal & metric data Unaffected by extreme scores
What is Probability Sampling?
Selecting the sample by means of random numbers
What does a Cross-Tabulation Table show?
Show the relationship between two or more variables -Its a multiple variable frequency table -Displays how the frequency or percentages of the categories of one variable are related to the frequencies of other variables
What is Absolute Frequency?
Simple counts for the number of cases per category
What is a Frequency?
Statistical term for a count of the number of cases in a particular category of a particular variable and the percentage of cases in a particular category of a particular variable
What do you do when a Median falls between 2 different quantity numbers?
Take the total sum of specific numbers to the left and the right of the line, divide that sum by the number of numbers used, that is the median. i.e. 8 + 8 + 9 + 9 + 9 + 9 = 52/6 = 8.7 Not 8.5
What is a Mean?
The arithmetic average of a group of scores -The sum of all the values of a variable divided by the number of values summed -Used only with ordinal (cautiously), interval and ratio (Metric) level data. -Most frequently encountered measure of central tendency -The mean score of a group is the best predictor of an individual score in that group -Tells us where the distribution of scores is centered, is the balance point
What is a Median?
The point at which 50% of the scores fall above and below. It is the "Middle Value" -Ordinal or metric variables -2nd most frequently encountered measure of central tendency
What are the characteristics of Frequency Polygons/Line Graphs?
Uses a single point instead of bars to convey the y-axis amount -Typically use interval or ratio level of measurement, but Can use ordinal level grouped data -Most prefer histograms to line graphs -Line graphs will require some groupings of data to display information
How to minimize bias?
Using unobtrusive measurement procedures; triangulation
What are the characteristics of a Histogram?
Utilizes ordinal, interval, or ratio levels of measurement (aka Metric) -B/c they represent quantitative increments we keep the bars side by side-moving from one bar to the next -Bar width can be proportional to variable's category frequency, but often times this is not done -Centered on X value -Represent quantitative increments -Well suited to grouped variables
Quiz 1 question: Because anyone can manipulate and distort statistics to support whatever point they are trying to make, it is best to ignore statistics rather than understand them.
o False x true
What is Absolute Frequency Distribution?
a table that displays the simple count (number) of cases in each category of a variable
What are benefits of Frequency Distributions?
able to see outliers able to look at atypical distributions able to see coding errors
What is Statistics?
analysis process for the data that you collect from the data collection as part of your research
How are specific statistical tests chosen?
based on level of measurement of data (variables)
How to determine Grouping Choice for Grouped Frequency?
depend on clinical judgment, literature review findings, and the natural distribution within the variable -you use your judgment in grouping choices by what provides the most meaningful portrayal of your data and makes sense from you research and experience
What is an ideal sample?
generalizable to the population
What is Reliability?
measures have reliability when they are consistent (reporting gender)
quiz 3 question: To simplify a frequency distribution for a variable that contains a large number of categories it is often helpful to create:
o A grouped frequency Distribution* x An absolute frequency distribution x A relative frequency distribution x A cumulative frequency distribution
quiz 3 question: Displays of simple counts of the number of cases per category are called:
o Absolute frequency distributions* x Relative frequency distributions x Cumulative frequency distributions x Grouped frequency distributions
quiz 3 question: Pie charts:
o All the above* x Portray frequency distribution data in terms of percentages represented by slices of a pie or sections of a circle x Show bigger slices of pie for categories with the higher percentages of cases x Work best when the number of categories being portrayed is not extensive
Quiz 1 question: Learning about statistics....
o All the below x Will help you be more effective in marshalling data to advocate for a new policy or program. x Will help you see through the misleading uses of statistics by your adversaries and to show others how their use of those statistics is misleading. x Will help you evaluate the effectiveness of your own practice.
quiz 3 question: The term frequency can refer to...
o Both a and b are true x The number of cases in a particular category of a particular variable x The percentage of cases in a particular category of a particular variable x None of the above is true
quiz 2 question: Descriptive statistics:
o Can include frequency distribution or measures of central tendency and dispersion.* x Typically involve analysis of Variance (ANOVA). x Tell us the probability that a given result can be attributed the chance. x All the Above
quiz 2 question: The safest way to obtain a representative sample is by using non-probability sampling procedures.
o False x True
quiz 2 question: Which of the following variables could NOT be collapsed to a lower level of measurement?
o Gender x Number of child neglect incidents. x Level of satisfaction with agency services. x Severity of trauma Symptoms
quiz 2 question: Evidence Based Practice
o Is a process for making practice decisions based on integrating the best research evidence with practice expertise and knowledge of client attributes* x Is a list of empirically supported interventions that practitioners should employ regardless of their practice judgment. x Is a process for making practice decisions based solely on research evidence. x Assures practice effectiveness.
quiz 3 question: Histograms:
o Look like bar graphs with bars that touch each other* x Work best with nominal level variables x Never can be used with values that are collapsed into grouped variables x Always have bars of equal width
quiz 3 question: The vertical line on a graph:
o Might display different levels of a second variable (or frequency), thus showing whether changing levels of categories on the variable on the horizontal axis move in a consistent fashion with changing levels of the second variable. * x Is called the x-axis x Never displays the number or percentage of cases for each value of a variable. x Is always a variable
quiz 2 question: At what level of measurement is the variable ethnicity?
o Nominal x Ordinal x Ratio x Interval
Quiz 1 question: Suppose a newspaper reports that the average number of times students in your college or university engage in binge drinking during the academic year is twice. What is appropriate to conclude?
o None of the below is an appropriate conclusion x The typical student binge drinks approximately twice per year x Most students binge drink approximately twice per year. x Both of the above are appropriate conclusions.
quiz 3 question: The best way to facilitate and simplify the interpretation of data collected in a large survey is to:
o Present a frequency distribution* x Display the spreadsheet raw data x Write a narrative detailing the number of cases for each attribute of each variable. x All the above
quiz 2 question: At what level of measurement is the variable number of future incidents of child neglect?
o Ratio x Ordinal x Nominal x Interventional
quiz 3 question: Displays of the proportions or percentages of cases per category are called:
o Relative frequency distributions* x Absolute frequency distributions x Cumulative frequency distributions x Grouped frequency distributions
quiz 3 question: Cross- tabulation tables:
o Show the relationship between two or more variables* x Always have only two rows and columns x Always have more than two rows and two columns x Always display frequencies only and not percentages
Quiz 1 question: Which of the following statements best depicts research findings on the effectiveness of interventions that have been popular among helping professionals and that have seemed theoretically sound?
o Some were found to be ineffective x None were found to be harmful x Earning a professional degree assures that your efforts to help people will be effective x All of the above are true
quiz 2 question: Inferential statistics:
o Tell us the probability that a given result can be attributed to chance x Are limited to describing a population x Always require the use of parametric tests. x Always require the use of nonparametric tests.
quiz 2 question: Is a father who is abusive consistently denies being abusive, his self-report is reliable but not valid.
o True x False
quiz 2 question: Meta-analyses review systematically existing studies and aggregate their statistical results.
o True x False
Quiz 1 question: An understanding of statistics helps practitioners in evaluating published research.
o True x false
Quiz 1 question: Keeping current with and critically appraising practice related studies and basing one's practice on evidence-based knowledge makes one a more ethical practitioner.
o True x false
Quiz 1 question: The most important reason why practitioners should learn about statistics is that they want to help people.
o True x false
Quiz 1 question: Understanding statistics makes one a more compassionate practitioner.
o True x false
quiz 2 question: A study is conducted to test the hypothesis that cognitive behavioral therapy is more effective than eclectic therapy in alleviating the severity trauma symptoms among female victims of rape? Which of the following is the independent variable in this study?
o Type of therapy x Gender x Severity of trauma symptoms x Cognitive behavioral therapy
quiz 3 question: Frequency polygons (line graphs):
o Typically involve interval-or ratio-level variables** x Use bars, just like bar graphs x Typically involve nominal-level variables x Never can be used with values that are collapsed into grouped categories
Quiz 1 question: Learning about statistics...
o Will help one avoid being misled by those who misuse statistics as a way to propagandize their political agenda x Is risky. x Is important despite its lack of relevance to practice. x Can interfere with one's capacity to be a warm, compassionate practitioner.
What do Graphs allow us to do?
presenting large amounts of data -display data meaningfully and visualize the meaning for extremely busy leaders -allow viewers to get the overall picture more quickly and simply than numbers, details, and tables
What is a Mediating variable?
variable that Accounts for the relation between the predictor and the criterion More than one variable that explains the effects of DV
What is a Moderating variable?
variable that Affects the direction and/or strength of the relation between an independent or predictor variable and a dependent or criterion variable Influences the strength of a relationship between two other variables
What is a Continuous variable?
variable that Takes any value between lowest and highest points on a scale
What is a Discrete variable?
variable that Takes only a limited number of values
What is an Independent variable?
variable that is Manipulated by the experimenter or measured prior to the dependent variable for the purpose of explanation or prediction
What is a Nominal level of measurement?
·Category -Equivalence, all members of category are same -Measured only in frequencies/counts with in category -Numbers are used to categorize, differentiate categories -Examples: Gender
What are the characteristics of a Pie Chart?
·Represent Frequency Distribution data in term of percentages represented by slices or sections -Bigger the slice, the larger the percentage of cases -Should be used for small number of categories with large numbers of frequencies -Normally used with Nominal data -That said, it could be used for "grouped" categories of a single variable