Unit 1
What function on your calculator do you use to find the probability of sampling a value within a specific range, in a normal graph?
NormalCDF(LB, UB, mean, SD) = P
Which axis (x or y) on the graph is typically the explanatory variable?
X - axis
What is a sample?
A representative subset of a population, examined in hope of learning about the population.
What is an outcome?
Result of a trial, which is measured, observed, or reported (ex. color of M&M pulled out of bag)
What function on the calculator do you use to find what proportion of data falls between a certain range on a normal distribution graph?
NormalCDF(LB,UB,U,SD)
What is a continuous variable?
a quantitative variable that can take on any value within a given range.
What is the correlation of a line?
The numerical measure r that measures the strength and direction of the linear relationship
What type of bias is caused when the respondent chooses to respond?
voluntary response bias
What is independence?
When the outcome of one trial does not influence the outcome of another. To assume independence, the sample must be random. P(A/B)=P(A)
What is the central limit theorem?
The condition that states that a dataset of a proportional analysis is normal if the number of samples per trial in a dataset is greater than or equal to 30
Z score is the number of _________ from the mean of a given value is.
standard deviations
What are residuals equal to?
Residual = actual value - predicted value
What types of bias does randomization eliminate?
selection bias and confounding bias
What qualifies events as mutually exclusive?
Two events do not share outcomes. Therefore, if A occurs, B cannot occur. (ex. playing card cannot be hearts and spades, so they are disjoint)
What is required of the 5 number summary?
Mean, STDEV, Min, Max, median
What is a discrete variable?
a type of quantitative variable that can only take on distinct, separate, and countable values, often whole numbers, representing things you can count, not measure, with no values in between possible.
What is R-squared an indicator of for a graph?
The proportion of variance in a dependent variable explained by independent variables in a regression model.
how does an observational study differ from an experiment?
An experiment actively manipulates variables, applies treatments (like a drug), and uses random assignment to establish cause-and-effect, while an observational study merely observes subjects in their natural setting without interference, identifying associations but not proving causation due to lurking variables.
How does increasing the number of trials affect the distribution of a graph?
The variance decreases, and the mean becomes more accurate.
What is an unbiased estimator?
a sample statistic whose expected value equals the true population parameter being estimated
Z = x-u/s
x= given value, u= mean, s= stdev
How do outliers affect the line of best fit?
significantly distort the line of best fit by pulling it towards themselves to minimize squared residuals. They alter the slope, shift the y-intercept, reduce the correlation coefficient (r), and weaken the overall predictive accuracy of the model.
P(X|Z) = ?
P(X∩Z)/P(Z)
What are the 3 conditions required to be met to find the probability of an event in a series of trials?
Normality: Large number counts
(np>10, )(n(1-p)>10)
Independence: n<10% of the population
Randomness: stated (SRS)
What percentage of data is between +2 and -2 of a normal distribution?
The empirical rule states that 95.44% of the data falls between this data range.