Straighterline Introduction to Statistics Exam 2023

Straighterline Introduction to Statistics Exam 2023 Four steps in the process of statistics - ANSWER 1. Producing Data 2. Exploratory Data Analysis 3. Probability 4. Inference Categorical variable - ANSWER places individuals into one of several groups Two types: nominal and ordinal Quantitative Variable - ANSWER represents a measurement or a count Two types: Interval and ratio Nominal Variable - ANSWER categorical variables where there is no natural order among the categories Ordinal variable - ANSWER categorical variables where there is natural order among the categories Interval Variable - ANSWER a measurement or count for which it makes sense to talk about the difference between values, but it does not make sense to talk about the ratio between values; 0 does not represent the absence of quanitity Ratio Variable - ANSWER quantitative variables for which it makes sense to talk about the difference between values AND the ratio between values; 0 represents the absence of quantity What type of variable?: eye color - ANSWER nominal What type of variable?: socioeconomic status with categories low, med, high - ANSWER Ordinal What type of variable?: Temperature - ANSWER Interval What type of variable?: Income - ANSWER Ratio Visual display and numerical summary for a single categorical variable - ANSWER pie chart or bar chart and category percentages Visual display and numerical summary for a single quantitative variable - ANSWER histogram or stemplot and descriptive statistics Visual display and numerical summary for C->C - ANSWER Two way table and conditional percentages Visual display and numerical summary for C->Q - ANSWER Side by side box plots and descriptive statistics Visual display and numerical summary for Q->Q - ANSWER Scatterplot and correlation coefficient (r) Standard Deviation Rule - ANSWER Approximately 68% of observations fall within 1 sd of the mean, 95% within 2 sd, 99.7% (or virtually all) within 3 sds Interquartile Range (IQR) - ANSWER Middle 50% of the data IQR= Q3- Q1 Finding an outlier using IQR - ANSWER An observation is considered a suspected outlier if it is: less than Q1 - 1.5(IQR), or more than Q3 + 1.5(IQR). Interpreting scatterplots: 1. positive relationship displays as 2. negative relationship displays as - ANSWER 1. upward slope 2. downward slope