CHAPTER 4
It shows the relationship between 2 quantitative variables measured on the same individual. The explanatory variable is plotted on the horizontal axis and the response variable is plotted on the vertical axis.
Scatter plot
The x variable is called the ____________ variable.
explanatory or predictor
The y variable is called the _____________ variable.
response variable
What does a positive association mean?
As one variable increases, so does the other.
Shows the number of proportion of individuals falling into categories defined by 2 or more variables.
Contingency table
The frequency distribution of each variable, which appears at the margin of the table is called a what?
marginal distribution
Correlation implies causation. True or false?
False
How do you determine if a linear relation exists between x and y when dealing with scatter plots?
If the absolute value of the correlation coefficient is greater than the critical value, then a linear relation exists. The absolute value is the "r" that you calculate from your calculator.
What does it mean if r=0?
No linear relationship exists between the variables.
If the linear correlation between the 2 variables is negative, what can be said about the slope of the regression line?
negative
The least squares regression line always travels through the point (x,y). True or false?
True
How do you find the sum of squared residuals in stat crunch?
Start out by clicking "stat", then going to regression and clicking on simple linear. Save the residuals and compute. After this, go to Data, then compute, then expression. Click Build and click on residuals and square that. After this new column has been added to the data set, then click on summary stats, columns, click residuals squared. Finally click sum and then compute to get your answer.
Difference between the observed value of the response variable y and the predicted value of y.
Residual
The ___________, R^2, measures the proportion of total variation in the response variable that is explained by the least squares regression line.
Coefficient of determination
Total deviation= __________ deviation + _____________ deviation
unexplained + explained
A ________________ is a scatter diagram with the residuals on the vertical axis and the explanatory variable on the horizontal axis.
Residual plot
Explain why correlations should always be reported with scatter diagrams
A scatter diagram is needed to see if the correlation coefficient is being affected by the presence of outliers.
CHAPTER 5
Any process with uncertain results that can be repeated
Probability experiment
A single execution or instance of a probability experiment is what?
Trial
The result of a single trial of the experiment, that is, the value measured, observed or reported for that trial.
Outcome
Any collection of outcomes from a probability experiment.
Events
An event that consists of one outcome.
Simple event
The collection of all possible outcomes
Sample space
What are the 2 rules of determining if something is a probability distribution?
All variables must be between 0 and 1 and the sum of all variables has to equal 1.
What is a unusual event?
Event that has a very low probability of occuring
What is the cutoff point?
Used to determine whether an event is unusual
How to tell if a probability is subjective.
It's subjective if it is based on people's opinion.
Two events are _________ if they have no outcomes in common.
Disjoint (mutually exclusive)
Two events (usually E and F) are ____________ if the occurence of event E in a probability experiment does not affect the probability of event F.
Independent
Two events are _______________ if the occurence of event E in a probability experiment affects the probability of event F.
Dependent
Order matters in permutation or combination?
It matters in permutation
Does order matter in combination?
no
Probability is a measure of the likelihood of a random phenomenon or chance behavior. True or false?
True
In probability, a ___________ is any process that can be repeated in which the results are uncertain.
experiment
If E and F are disjoint events, then P(E or F)=
P(E) + P(F)
If E and F are not disjoint events, then P(E or F)=
P(E) + P(F) - P(E and F)
What is the general addition rule?
P(E or F)= P(E) + P(F) - P(E and F)
The word "and" in probability implies that we use the _______________ rule.
Multiplication
The word "or" in probability implies that we use the ____________ rule.
Addition
A _______ is an ordered arrangement of r objects chosen from n distinct objects without repetition.
Permutation
What method of assigning probabilities to a simple event uses relative frequencies?
Empirical
CHAPTER 6
What is the numerical measure of the outcome of a probability experiment, so its value is determined by chance.
Random variable
List of probabilities associated with each of its possible values.
Probability distribution
A histogram in which the horizontal axis corresponds to the value of the random variable and the vertical axis represents the probability the random variable takes that particular value.
Probability histogram
Expected value of the squared deviation from the mean.
Variance
Describes the spread in the model, and is the square root of the variance.
Standard deviation
What are the rules for the binomial probability experiment?
1. Has to be performed a fixed number of times.
2. The trials are independent.
3. There has to be 2 mucually exclusive outcomes, success or failure.
4. The probability of success is fixed.
What does "At least" or "no less than" or "greater than or equal to" refer to?
What does "more than" or "greater than" refer to?
What does "fewer than" or "less than" refer to?
What does "no more than", or "at most", or "less than or equal to" refer to?
What does "exactly", "equals" or "is" refer to?
What are the rules for the hypergeometric probability distribution?
1. A finite population is sampled without replacement.
2. For each trial, there are 2 possible outcomes (success or failure)
What does the variable N stand for?
the population
What does the variable n stand for?
sample
What does k stand for?
the successes in the population
What is the formula for finding the mean of a hypergeometric random variable?
n x k/N
What is true about the mean?
As the number of experiments increases, the mean of the observations will approach the mean of the random variable.
A binomial experiment is performed a fixed number of times. What is each repetition of the experiment called?
a trial
In the binomial probability distribution, n C x, what does x represent?
successes in n trials
How does the value of n affect the shape of the binomial probability histogram?
as n increases, the binomial distribution becomes more bell shaped.
When can the Empirical rule be used to identify unusual results in a binomial experiment?
When the binomial distribution is approximately bell shaped, about 95% of the outcomes will be in the intervall from u-2o to u+2o.
Why can the Empirical Rule be used to identify results in a binomial experiment?
The Empirical Rule can be used to identify results in binomial experiments when np(1-p ) is greater than or equal to 10.