Data-Driven Decision Making (C207) - WGU 2023 Questions and Answers

Random Errors - Answer Error in measurement caused by unpredictable statistical fluctuations Information Bias - Answer A prejudice in the data that results when either the respondent or the interviewer has an agenda and is not presenting impartial questions or responding with truly honest responses, respectively Ratio Data - Answer Similar to interval data in that the data is ordered within a range and with each data point being an equal interval apart, also has a natural zero point which indicates none of the given quality Data Set - Answer A collection of related data records on a storage device. Nominal Data - Answer Sometimes called categorical data or qualitative data, this data type is used to label subjects or data by name Reliable Data - Answer Data that is consistent and repeatable Davenport-Kim Three Stages Model - Answer A decision-making model developed by Thomas Davenport and Jinho Kim that consists of three stages: Framing the problem Solving the problem Communicating the problem Blind study - Answer A study performed where the participants are not told if they are in the treatment group or control group Double-Blind Study - Answer A study performed where neither the treatment allocators nor the participant knows which group the participant is in Measurement Bias - Answer A prejudice in the data that results when the sample is not representative of the population being represented. Analytics - Answer The discovery, analysis, and communication of meaningful patterns in data. Data Management - Answer The management, including the cleaning and storage, of collected data Triple-Blind Study - Answer A study performed where neither the treatment allocator nor the participant nor the response gatherer knows which group the participant is in Omission Error - Answer An error because something ( for example, data or survey responses) is missing. Relational Database - Answer A database structured to recognize relations among stored items of information Ordinal Data - Answer Data that places data objects into an order according o some quality with higher order indicating more of that quality Discrete Data - Answer Data that can only take on whole values and has clear boundaries Interval Data - Answer Data that is ordered within a range and with each data point being an equal interval apart Valid Data - Answer Data resulting from a test that accurately measures what it is intended to measure Big Data - Answer A catch-phrase that describes a massive volume that is so large that it's difficult to process using traditional database software techniques Systematic errors - Answer Errors in measurement that are constant within a data set, sometimes caused by faulty equipment or bias. Benchmarks - Answer Standards or points of reference for an industry or sector that can be used for comparison and evaluation. Continuous Data - Answer Data that can lay along any point in a range of data Statistics - Answer The science that deals with the interpretation of numerical facts or data though theories of probability. Also, the numerical facts or data themselves. Decision Tree Analysis - Answer The diagram of possible alternatives and their expected consequences in order to formulate passible courses of action in order to make decisions Expected Monetary Value (EMV) Analysis - Answer A statistical technique that calculates the average outcome when the future includes scenarios that may or may not happen. Response Rates - Answer The number of people who respond to a marketing offer (often expressed as a percentage of the number of responses divided by the number of people that ere targeted mail, email etc.) Click-through rates - Answer A common metric to measure the success of an email campaign. Total number of clicks on a hotlink(s) in an email divided by the number of emails sent. Includes multiple clicks by a unique user. Open Rate - Answer The number of email message recipients who opened an email, usually as a percentage of the number of emails sent or delivered. The open rate is considered a key metric for judging an email marketing campaign. Transactional Data - Answer Data that records a time and relevant reference data needed for a particular transaction record; can be financial, involving everything from a purchase to shipping status to a product return. Response Bias - Answer When respondents to a survey say what they believe the questioner wants to hear. This bias can occur as a result of the wording of a question. Conscious bias - Answer The surveyor is actively seeking a certain response to support his or her cause. Bias occurs when the researcher manipulates the phrasing of questions in order to elicit the desired response Missing data and refusals - Answer This misuse occurs when a certain part of the sample gets lost or subjects refuse to contribute ti the overall data collection Small sample size - Answer Sample size is too small to make inferences Parametric test - Answer Assumes there is a structure (maybe a normal distribution) to the population, often appearing when mean or standard deviation are important Non-parametric test - Answer Does not assume there to be a structure (maybe a normal distribution) to the population Association and causality misuse - Answer When a researcher notices a relationship between two variable and assumes that one variable is the cause of the other. In reality, these variables might both be caused by separate variables; they would merely be correlated. Or have no relationship at all. Training and test data misuse - Answer When the same dat that's used to forma hypothesis is then used to test the hypothesis. Sample size is too small and different samples have a lot of crossover Unfounded assumptions - Answer Assumption is made that has not been proven Operationalization - Answer The development of specific research procedures that allow for observation and measurement of abstract concepts. Key aspects of operationalizing is defining variables and attributes that adequately represent the concepts of the study. Blinding - Answer When researchers place barriers between themselves and subjects to insure the researchers do not influence subjects' behavior. Causation - Answer Cause and effect Confidence Interval - Answer The range around the mean that a sample has a specific probability of occurring within Probability - Answer The likelihood of an event occurring Compliment - Answer The occurrence of an event not happening, the opposite. The sum of the probability and its compliment is always equal to one. Independent Events - Answer Events that are not effected by other trials or events, Complimentary events - Answer Events with two outcomes that are the only possible outcome. Like flipping a coin. Conditional Probability - Answer The probability of an event occurring, given that another event has already occurred. P(B|A) = P(A and B)/P(A) Dependent Events - Answer An event that is affected by the previous events. Probability of an Intersection - Answer The probability of two independent events happening. P(A∩B) = P(A) x P(B) Probability of a Union - Answer The collection of elements that are both A, B or both A and B. P (AUB) = P (A) + P (B) - P (A∩B) Mutually Exclusive Events - Answer When two or more events are not able to occur at the same time Multiplication Principle - Answer When the probabilities of multiple events are multiplied together to determine the likelihood of all the event occurring. Inferential Statistics - Answer Statistics that are used to make predictions about a population from observations of a sample Descriptive Statistics - Answer Used to describe a population from observations of that whole population Sampling with Replacement - Answer A technique used when each piece of the population can be selected more than once. If sampling with replacement and taking a sample of size n from a population of z, there are z^n possible outcomes. Sampling without Replacement - Answer A technique used when each piece of the population can only be selected once. If you take a sample size of n without replacement, there are usually n! (n factorial) possible outcomes. i.e. n! = 6! = 6 x 5 x 4 x 3 x 2 x 1 = 720 Permutations - Answer The number of unique ordered possibilities for a certain situation. nPk=n!/(n-k)! i.e. n= Number of people P= permutations k= number of available seats Factorial Operation - Answer n! or i.e. 5!=5*4*3*2*1=120 or 3!=3*2*1=6 Combination - Answer The number of unique possibilities for a certain situation. nCk aka the binomial coefficient n!/k!(n-k)! Baye's Theorem - Answer If you know the probability of event A, the probability of event B, and the conditional probability of event A given event B, we can determine the probability of event B given event A. P(A|B) = P(B|A)*P(A) / P(B) Conditional Probability - Answer The probability of an event occurring given that another event has occurred. Population variance - Answer where: σ2 = the population variance μ = the population mean ∑(x - μ)2 = the sum of the squared differences between each data point and the mean. That is, you square each data point's difference from the mean, then add these squared numbers together N= the size of the population Population Standard Deviation - Answer where: σ2 = the population variance μ = the population mean ∑(x - μ)2 = the sum of the squared differences between each data point and the mean. That is, you square each data point's difference from the mean, then add these squared numbers together N= the size of the population Remember, population standard deviation (σ) is the square root of population variance. Sample Variance - Answer where: s2 = the sample variance x = the sample mean ∑(x - x)2 = the sum of the squared differences between each data point and the mean. That is, you square each data point's difference from the mean, then add these squared numbers together n= the sample size Sample Standard Deviation - Answer where: s2 = the sample variance x = the sample mean ∑(x - x)2 = the sum of the squared differences between each data point and the mean. That is, you square each data point's difference from the mean, then add these squared numbers together n= the sample size Remember, sample standard deviation (s) is the square root of sample variance. Bassel's correction - Answer The replacement of N with n - 1 yields a more accurate number for a sample — especially a small sample. When the size of the sample (n) is very large, the difference between the population and sample variances and standard deviations becomes very small. Quartile - Answer Four equal groups into which a population can be divided. Interquartile - Answer The difference between the third quartile and the first quartile. To determine the first and third quartiles, order the data from lowest value to highest value. Then separate the data into four equal groups. Histograms - Answer Measures how continuous data is distributed over various ranges. A graph that displays continues data. Bar Graph - Answer Measures data that is distributed over groups or categories. Proportion - Answer A type of ratio where the number of observations that are part of a specific group is compared to the total relevant population. Probability Distribution - Answer A list of all of the different probabilities of each outcome that can occur. This is often displayed as a graph, table, or formula Probability functions - Answer Functions that assign probabilities to values of a random variable, determine the information in a probability distribution. Needs to have the sum of the probability values equal to one and also needs each probability value to be greater than zero and less than one. P(X) = { P(2-9) = 0.615 P(10-K) = 0.308 P(A) = 0.077 } - Answer A probability distribution is displayed as a function it shows the probability of each outcome. (This example is drawing a card from a suit Probability density functions are used for.... - Answer Continuous random variables. A probability distribution is continuous if there is any number of outcomes in a range. Like temperature. Probability mass functions are used for.... - Answer Discrete random variables. A probability distribution is discrete if there are a defined number of outcomes. Like working computers or being pregnant; you are or you are not. Cumulative distribution - Answer represents the probability that a variable falls within a certain range. Specifically, the cumulative distribution of x measures the probability that a variable is less than or equal to x. Cumulative distributions, as they are progressing through the data should approach 1.0 or 100% of its data. Central Limit Theorem - Answer The idea that if a great enough number of samples is taken, the means of those samples will be normally distributed around the population mean. As more samples are taken, the sample mean will approach the population mean. Confidence intervals - Answer The range around a sample mean that has a specific probability of containing the true population mean. The "confidence" is the likelihood that a new sample will look like past findings, while the "interval" is the varying range around the existing mean that allows for the different levels of confidence. Standard error of the mean - Answer Used to give an estimate of the proximity of the sample mean to the population mean. null hypothesis, or H0 - Answer The statement that there is no relationship. For whatever relationship is being tested, the null hypothesis is the statement that the relationship does not exist. The null hypothesis is always the statement that is being tested. alternative hypothesis, or HA, - Answer It is the opposite statement to the null hypothesis. It states that there is a relationship for whatever relationship is being tested. Statistically significant - Answer A result is unlikely to be caused by random variation or errors. Significant difference - Answer A difference that is statistically significant The null hypothesis statement can be written as: - Answer H0: μ1 = μ2 The alternative hypothesis can can be written as: - Answer HA: μ1 ≠ μ2 Significance level - Answer a decision criterion that specifies the degree of certainty with which you want to make your judgment of whether or not to reject the null hypothesis. Critical value - Answer The tipping point between where we reject the null hypothesis and where we fail to reject the null hypothesis. Linear Programing - Answer A mathematical technique used to find a maximum or minimum of linear equations containing several variables. The Simplex Method - Answer A complicated mathematical method that helps solve linear programming problems. Crossover Analysis - Answer Allows a decision maker to identify the crossover point, which represents the point at which we are indifferent between the plans. A chi-squared test (also written as "Χ2" or "chi-square") - Answer A chi-squared test is commonly used in statistics to draw inferences about a population, by testing sample data. Employed for categorical data Chi-Squared Test Formula - Answer Χ2 = Σ(o - e)2/e where: o = the observed value in any given category. e = the expected value in any given category. The Empirical Rule, - Answer Approximately 68.3% of the data points in a dataset will be within 1 standard deviation of the mean. Approximately 95.4% of the data points in a dataset will be within 2 standard deviations of the mean. And almost all (99.7%) of the data points in a dataset will be within 3 standard deviations of the mean. ANOVA - Answer Analysis of Variance is a technique used to determine if there is a significant difference among three or more means. Regression Analysis definition - Answer Statistical method to measure the average amount of change in a dependent variable associated with a unit change in one or more independent variables; considered an associate model as it incorporates the factors (variables) that might influence the quantity being forecasted Time Series Analysis - Answer Forecasting technique that employs a series of past data points to make a forecast