Stats 101 Short Answers Flashcards
How do we Plot One Numeric Variable?
Dot/box plots.
How do we Plot One Categorical Variable?
Frequency table, bar chart.
How do we Plot Two Numeric Variables?
Scatter plots.
How do we Plot One Numeric and One Categorical Variable?
Side by side plots with same scale.
How do we Plot Two Categorical Variables?
Two way table of counts, side by side bar charts.
What is a Cross-Section Observational Study?
Group of individuals at a point in time.
What is a Longitudinal Observational Study?
Group of individuals over a long period of time.
What does the Standard Error of the Sampling Mean Measure?
The average distance between a sample mean and the population mean.
How do we Calculate Confidence Intervals?
Estimate ± t x se(estimate).
What are the Symbols for a Single Mean as a Parameter and an Estimate?
Parameter = μ Estimate = x̄
What are the Symbols for a Single Proportion as a Parameter and an Estimate?
Parameter = p Estimate = p̂
How do you Build a Bootstrap Confidence Interval?
From original sample randomly sample until resamples match original sample size, calculate an estimate, do many resamples with many estimates, use central 95% to find upper and lower limits.
How do we Produce a Confidence Interval by Hand?
State the parameter, state the estimate, write down formula, use the given standard error, use the given t-multiplier, calculate confidence limits, interpret in plain English.
What Happens to the T-Multiplier when the Level of Confidence Increases?
It also increases.
What are 3 Effects of Increasing Confidence Level?
Increased t-multiplier, increased width of confidence interval, estimate statement is less precise.
What are 4 Effects of Increasing Sample Size?
Decrease standard error of estimate, decrease t-multiplier in terms of means, decrease width of confidence interval, estimate statement is more precise.
What can we Infer from a Random Assignment of Units to Groups?
Experiment-to-causation.
What can we Infer from a Random Sampling of Units?
Sample-to-population.
How do you Perform a Hypothesis Test by Hand?
State parameter, state null hypothesis, state alternative hypothesis, state estimate, calculate test statistic, estimate p-value, interpret p-value, calculate confidence interval, interpret in plain English, conclude.
What is the Only Form of the Null Hypothesis?
Ho: parameter = hypothesised value.
What is the 2-Sided Form of the Alternative Hypothesis?
H1: Parameter ≠ hypothesised value.
What are the 2 1-Sided Forms of the Alternative Hypothesis?
H1: Parameter < hypothesised value.
H1: Parameter > hypothesised value.
What Does a Higher Test Statistic Mean?
Greater evidence against the null hypothesis.
What Does a Lower P-Value Mean?
Stronger evidence against the null hypothesis.
What is the Critical P-Value?
0.05.
