Descriptive Statistics
This measure of center is more resistant to outliers than the mean.
What is the median?
Neither the subject nor those who measure the reponse variable know which treatment a subject received.
What is a double blind experiment?
The slope in the least-square regression line, y = 15 - 4x.
What is "For every one unit increase in the explanatory variable, we predict a 4 unit decrease in the response variable"?
This type of random variable requires a fixed number of trials.
What is a binomial random variable?
t-distributions are distinguishable from one another by this statistical measure.
What are degrees of freedom?
To calculate, subtract the mean of the distribution from the observed x, then divide by the standard deviation.
What is a z-score?
A common form of blocking for comparing just two treatments.
What is matched pairs?
A z-score of -3.45
What is, "The data value is 3.45 standard deviations below the mean"?.
The type of variable where the probability distribution assigns probability as the area under the density curve above a specific interval.
What is a continuous random variable?
Generally speaking, if the size of the sample is not greater than 30, then the condition that must be met in order for us to say that the sampling distribution of the sample mean is approximately normal is this.
What is, the population distribution is approximately normal?
Measures the direction and strength of a linear relationship between two quantitative variables.
What is correlation r?
When some groups in the population are left out of the process of choosing a sample.
What is selection bias (undercoverage)?
An r-squared value of 0.85.
What is, "85% of the variation in the y-variable can explained by our linear regression model?"
Events that have no outcomes in common and can never occur simultaneously, for which the addition rule is used.
What are disjoint or mutually exclusive events?
When the mean of the sampling distribution of a statistic is not equal to the parameter, we say the statistic is this.
What is biased?
Observed y - predicted y
What is a residual?
The population is divided into groups. Some groups are randomly selected and all individuals in the chosen groups are sampled.
What is cluster sampling?
Interpret the standard deviation of a sampling distribution of the sample proportion.
What is, "A typical deviation of the sample proportions from mean of the sampling distribution of the sample proportion (population proportion)?"
Given that some event E has happened, if the probability of F happening is equal to the probability of F, then we say the events E and F are this.
What is independent?
We can use a one-sample t-interval when estimating a population mean given these three conditions.
What is,
1. the population standard deviation is unknown.
2. The sample size is sufficiently large or the population distribution is approximately normal.
3. The sample size is less than 10% of the population size.
Applying a logarithmic transformation to both variables causes this type of model to become linear.
What is a power model?
The effects of two variables on the response cannot be distinguished from each other.
What is confounding?
95% Confidence level for a population mean.
What is, "This interval was created using methods that capture the true mean 95% of the time?"
Also acceptable: "After repeatedly sampling, we would find that the true mean would be captured by 95% of the intervals associated with the sample means."
Thirty percent of all automobiles undergoing an emissions inspection at a certain inspection station fail the inspection. Let x be the number of inspections that must be performed before a failure is observed. P(x) has this type of distribution.
What is a geometric distribution?
Suppose we take a sample of size n=10 from an approximately normal population, and we measure the mean to be xbar=10 and standard deviation s=2. Determine the width of a 98% confidence interval for the population mean.
What is 11.78-8.22=3.57?