Confidence Intervals
This value is added to and subtracted from a point estimate to create a confidence interval.
What is the margin of error?
If the p-value is less than the significance level, we do this to the null hypothesis.
What is reject?
This kind of study can show association but not causation.
What is an observational study?
When two events cannot happen at the same time, they are called this.
What are mutually exclusive events?
The direction, form, and strength of a relationship are often described for this kind of graph.
What is a scatterplot?
This statistic measures the strength and direction of a linear relationship between two quantitative variables.
What is correlation or r?
As the confidence level increases, the confidence interval generally becomes this.
What is wider?
This is the probability of getting a result at least as extreme as the observed one, assuming the null hypothesis is true.
What is the p-value?
This design feature helps balance lurking variables among treatment groups.
What is random assignment?
If two events are independent, then P(A and B) equals this.
What is P(A)⋅P(B)?
This resistant measure of spread is found by subtracting the first quartile from the third quartile.
What is the interquartile range (IQR)?
This graph is used to assess whether a linear model is appropriate by plotting residuals against the explanatory variable or predicted values.
What is a residual plot?
This is the midpoint of a one-sample confidence interval for a proportion.
What is the sample proportion?
Rejecting a true null hypothesis is called this type of error.
What is a Type I error?
This design feature allows researchers to generalize to a population.
What is random sampling?
This sampling method divides the population into groups, then randomly selects some of those groups and surveys everyone in the chosen groups.
What is cluster sampling?
In a residual plot, a random scatter around 0 suggests this model may be appropriate.
What is a linear model?
This value is interpreted as the predicted change in y for a one-unit increase in x.
What is the slope?
If all other conditions stay the same, increasing the sample size makes a confidence interval do this.
What is become narrower?
Failing to reject a false null hypothesis is called this type of error.
What is a Type II error?
When subjects in similar groups are first grouped and then randomly assigned within groups, this is called this.
What is blocking?
This sampling method gives every group member the same chance of selection and is often abbreviated SRS.
What is a simple random sample?
When comparing distributions, this feature describes whether the data are concentrated around one center, spread out, or tightly clustered.
What is spread?
If a residual plot shows a clear curved pattern, this suggests that this type of model may not be appropriate.
What is a linear model?
When sample size increases, the margin of error for a confidence interval generally does this.
What is decreases?
A small p-value provides strong evidence against this hypothesis.
What is the null hypothesis?
If neither subjects nor evaluators know which treatment was given, the experiment is described this way.
What is double-blind?
As sample size increases, the sampling distribution of the sample mean becomes more nearly this shape.
What is normal?
In a distribution, this standardized score tells how many standard deviations an observation is above or below the mean.
What is a z-score?
This statistic gives the proportion of variation in the response variable explained by the least-squares regression line.
What is r2?