Statistical Data Literacy D772 Study Guide With Practical Questions An Answers

an unbiased sample, is a subset of the population that accurately reflects the characteristics of the larger group - Correct Answers representative sample a biased sample, fails to accurately reflect the population - Correct Answers non-representative sample individuals have selected themselves to be included - Correct Answers volunteer sample occurs when sample members are self-selected volunteers, as in voluntary samples likely only people with strong opinions will volunteer, leading to misrepresentation of data - Correct Answers voluntary response bias individuals are selected based on the convenience of the researcher, often because they happen to be at the right time and place May create bias because may favor people based on time and location - Correct Answers convenience sample Every nth item in the target population is selected May create bias if there are underlying patterns in directory - Correct Answers systematic sampling bias introduced to a sample when a large fraction of those sampled fails to respond There is a danger that those who do respond are different from those who don't, with respect to the variable of interest - Correct Answers nonresponse bias list of potential individuals to be sampled - Correct Answers sampling frame a mismatch that may not be representative of your entire desired population - Correct Answers sampling frame error where the researchers have a vested interest in the outcome - Correct Answers self-interest study Occurs when the responder gives inaccurate responses for any reason, such as misunderstanding the question or feeling pressured to provide a certain answer - Correct Answers response bias A type of response bias which occurs when the responder fears giving an honest answer might negatively affect them, leading to dishonest or misleading responses - Correct Answers perceived lack of anonymity Occurs when the question wording influences the responses, leading to biased results. - Correct Answers loaded or leading question -manipulation of the y axis to distort differences -inconsistent intervals on the x axis -use of images that scale in more than one dimensions than appropriate for the data - Correct Answers ways to distort a graph t is unlikely that the result we measured differed from the expected result solely because of random chance - Correct significant The first is the sample size. The larger the sample size, the less likely it is for random chance to produce results that are notably different from their true value The second is the extremeness of the observed result. If our result is very different than we would expect, it has a greater likelihood of being statistically significant - Correct Answers Two primary factors impact statistical significance Presenting data in a way which is likely to mislead those viewing it or cause them to draw incorrect conclusions. - Correct AnswersMisrepresenting data Deliberately creating a data set that is inconsistent with or unsupported by the results of the study, or that is achieved through improper research practices. - Correct AnswersFalsifying data two variables are related in some way, but this relationship may not be direct, and there may be no cause-and-effect relationship between them. Often found in observational studies - Correct Answersassociation one variable directly causes an effect in the other. - Correct Answerscausal relationship a variable that is not accounted for, but that may influence the relationship being studied because it is associated with both the explanatory and response variable - Correct Answersconfounding variable more likely to reveal a casual relationship between variables - Correct Answersexperimental studies The data points form a clear pattern which closely resembles a straight line. - Correct AnswersLinear The data points form a clear pattern, but that pattern is something other than a line (such as a curve). - Correct AnswersNonlinear The data points appear to be scattered randomly throughout the graph with no discernible pattern. - Correct AnswersNo pattern (No correlation Data that describes qualities using names, labels, or categories EX Hair color (black, dark brown, light brown, blonde, gray, red), blood type (AB, O, B), ethnic group, car model, street address - Correct AnswersCategorical Data Data based on a numerical measurement EX Amount of money, pulse rate, weight, number of people living in a town, number of students taking statistics - Correct AnswersQuantitative Data The variable which may explain or cause an effect in the response variable - Correct AnswersExplanatory Variable The variable which is potentially affected by the explanatory variable - Correct AnswersResponse Variable pie charts bar graphs - Correct Answersways to represent categorical data organizes quantitative data by splitting values into a stem and a leaf. The leaf is the right-most digit, and the stem is all the proceeding digits - Correct Answersstem-and-leaf plot a number line and dots (or points) positioned above the number line - Correct Answersdot plot stem and leaf plots dot plots histograms - Correct Answersways to represent qualitative data a chart which displays quantitative data by grouping it into intervals (also called bins or classes) of a set width on the x-axis. - Correct Answershistogram classification of the variables (response and explanatory) into categorical and quantitative - Correct Answersrole-type classification appropriate graph to represent a C→C (Categorical to Categorical) role-type classification - Correct Answerstwo-way table appropriate graph to represent C→Q (Categorical to Quantitative) role-type classification - Correct Answersside-by-side boxplot appropriate graph to represent a Q→Q (Quantitative to Quantitative) role-type classification - Correct Answersscatterplot a data set where if a line were drawn through the middle of the distribution, the two sides would appear approximately as mirror images unimodal, bimodal, and uniform - Correct Answerssymmetric distribution The first distribution has one mode (roughly at 10) around which the observations are concentrated. - Correct AnswersUnimodal The second distribution has two modes (roughly at 10 and 20) around which the observations are concentrated. - Correct AnswersBimodal The third distribution is approximately flat, with no modes. Observations are roughly equally (or uniformly) distributed among the different values. - Correct AnswersUniform data points are stretched further on one side of the distribution, creating a curve that is not symmetric - Correct AnswersSkewed Distribution number of peaks (modes) in a distribution of data - Correct Answerspeakedness (modality) distribution where the right tail (larger values) is much longer than the left tail (smaller values). - Correct Answersskewed-right distribution where the left tail (smaller values) is much longer than the right tail (larger values). - Correct Answersskewed-left distribution that occurs frequently in nature, science, and mathematics that are unimodal, symmetric, and roughly bell-shaped. - Correct Answersnormal distributions The average of a set of numbers - Correct Answersmean the middle value in the data set - Correct Answersmedian the most frequent value in the data set - Correct Answersmode values that divide an ordered data set into four equal parts The first quartile, Q1, is the same as the 25th percentile. The second quartile, Q2, is the same as the 50th percentile, also called the median. The third quartile, Q3, is the same as the 75th percentile - Correct AnswersQuartiles a measure of spread calculated as the difference between the highest data value (the maximum) and the lowest data value (the minimum). - Correct Answersrange Minimum Q1 Median (Q2) Q3 Maximum - Correct Answersfive-number summary