Exploring Data
Q: What is a histogram used for?
A: Displaying the distribution of quantitative data.
Q: What does the slope of a regression line represent?
A: The change in y for each unit change in x
Q: What is the probability of an impossible event?
A: 0
Q: What is a confidence Interval?
A: A range of values likely to contain the population parameter.
Q: When do we use a t-distribution?
A: When the population standard deviation is unknown.
Q: What does the median represent?
A: The middle value of an ordered data set
Q: What is the y-intercept?
A: The predicted value of y when x is 0
Q: What is the complement rule?
A: P(not A)= 1-P(A)
Q: What affects the width of a confidence Interval?
A: Sample size and confidence level
Q: What is the null hypothesis in a t-test?
A: That the population mean equals a specific value.
Q: What is a categorical variable?
A: A variable that describes categories or groups
Q: What does R-squared represent?
A: The proportion of variability explained by the model
Q: What is the addition rule for disjoint events?
A: P(A or B)= P(A) + P(B)
Q: What does "95% confident" mean?
A: In repeated samples, 95% of confidence intervals would contain the true parameter
Q: What does a small P-value indicate?
A: That there is strong evidence against the null hypothesis
Q: What is standard deviation
A: A measure of the spread of a distribution
A: The difference between actual and predicted value
Q: What is the multiplication rule for independent events?
A: P(A and B)= P(A) x P(B)
Q: How do you increase precision?
A: Increase sample size or decrease confidence interval
Q: What condition must be checked for t-tests?
Q: What is the purpose of using z-scores in comparing distributions?
A: To standardize values and compare different distributions
Q: What is an influential point in regression?
A: A point that significantly affects the slope or intercept of the regression line.
Q: What is conditional probability?
A: The probability of one event occurring given that another has occurred.
Q: Why do we use margin of error in Confidence Intervals?
A: To account for variability in the estimate and create a range for the parameter
Q: What is the purpose of a matched pairs design?
A: To reduce variability and control for confounding variables.