IDS 270 QUESTIONS AND ANSWERS SURE A+
✔✔Define: Finite sample space - ✔✔Way to assign probabilities to a discrete variable
✔✔Define: Continuous variable
Between what two numbers? - ✔✔Variable that has values that continue smoothly on a
scale. not integers Between 0 and 2.
✔✔Define: Infinite sample space - ✔✔Way to assign probabilities to ranges of events
for a continuous variable
✔✔Define: Random variable (2 things) - ✔✔1. Produces only numbers
2. Driven by random process
ex. count the number of defective products coming from an assembly line.
✔✔Define: Explanatory variable
What is a synonym for this term? - ✔✔The thing that we have be different for different
individuals in order to measure the association with the response variable
Synonym: independent variable
ex. Amount of exercise- explanatory and its effect on weight loss ( response variable)
✔✔Define: Response Variable synonym - ✔✔Dependent Variable
✔✔Define: Marginal distribution - ✔✔Values for one variable if we ignore the categories
of the other variable
✔✔Define: Conditional distribution - ✔✔Values for one variable after holding another
variable to a single value
, ✔✔Define Simpson's Paradox - ✔✔
✔✔Why could there be a difference between two departments? (3) - ✔✔Outliers, right-
skewed charts, lurking variables
✔✔When and only when can you compare the means of two charts? - ✔✔If they are
symmetric
✔✔Why could there be a difference between two departments? - ✔✔Outliers, right-
skewed charts, lurking variables
✔✔Define: Subjects - ✔✔People who are involved in an experiment
✔✔Matched pairs design - ✔✔Match two subject based on similar values of an
independent or potentially confounding variable. Randomly put on subject in one
treatment, the other subject in the other treatment.
✔✔block design - ✔✔matched pairs design with more than 2 treatments
✔✔the pieces of a probability model - ✔✔S, event, probability to assign chances of
seeing the event occur
✔✔average from a sample - ✔✔x-bar ( x with a horizontal line over the top
✔✔standard deviation of a sample - ✔✔S
✔✔average of a population or probability model - ✔✔greek letter mu
✔✔standard deviation of a population or probability model - ✔✔greek letter sigma
✔✔calculate standard deviation - ✔✔each point subtracted by mean, squared added
together
divided by n-1, n being the size of the pop. sample.
ex.
2468
(2-5)^2 + (4-5)^2 + (6-5)^2 + (8-5)^2 = 9+1+1+9= 20/3.(variance)
square root of 20/3= standard deviation
✔✔standard deviation represents; - ✔✔the average distance of the data points to the
mean. squaring is done to remove negative distances.
✔✔general intelligence test normally distributed has a mean of 600 and a standard
deviation of 60. What percet of test takers can expect to score between 540 and 680.? -
✔✔SO, you do X to Z to % for both numbers 540 and 680.
✔✔Define: Finite sample space - ✔✔Way to assign probabilities to a discrete variable
✔✔Define: Continuous variable
Between what two numbers? - ✔✔Variable that has values that continue smoothly on a
scale. not integers Between 0 and 2.
✔✔Define: Infinite sample space - ✔✔Way to assign probabilities to ranges of events
for a continuous variable
✔✔Define: Random variable (2 things) - ✔✔1. Produces only numbers
2. Driven by random process
ex. count the number of defective products coming from an assembly line.
✔✔Define: Explanatory variable
What is a synonym for this term? - ✔✔The thing that we have be different for different
individuals in order to measure the association with the response variable
Synonym: independent variable
ex. Amount of exercise- explanatory and its effect on weight loss ( response variable)
✔✔Define: Response Variable synonym - ✔✔Dependent Variable
✔✔Define: Marginal distribution - ✔✔Values for one variable if we ignore the categories
of the other variable
✔✔Define: Conditional distribution - ✔✔Values for one variable after holding another
variable to a single value
, ✔✔Define Simpson's Paradox - ✔✔
✔✔Why could there be a difference between two departments? (3) - ✔✔Outliers, right-
skewed charts, lurking variables
✔✔When and only when can you compare the means of two charts? - ✔✔If they are
symmetric
✔✔Why could there be a difference between two departments? - ✔✔Outliers, right-
skewed charts, lurking variables
✔✔Define: Subjects - ✔✔People who are involved in an experiment
✔✔Matched pairs design - ✔✔Match two subject based on similar values of an
independent or potentially confounding variable. Randomly put on subject in one
treatment, the other subject in the other treatment.
✔✔block design - ✔✔matched pairs design with more than 2 treatments
✔✔the pieces of a probability model - ✔✔S, event, probability to assign chances of
seeing the event occur
✔✔average from a sample - ✔✔x-bar ( x with a horizontal line over the top
✔✔standard deviation of a sample - ✔✔S
✔✔average of a population or probability model - ✔✔greek letter mu
✔✔standard deviation of a population or probability model - ✔✔greek letter sigma
✔✔calculate standard deviation - ✔✔each point subtracted by mean, squared added
together
divided by n-1, n being the size of the pop. sample.
ex.
2468
(2-5)^2 + (4-5)^2 + (6-5)^2 + (8-5)^2 = 9+1+1+9= 20/3.(variance)
square root of 20/3= standard deviation
✔✔standard deviation represents; - ✔✔the average distance of the data points to the
mean. squaring is done to remove negative distances.
✔✔general intelligence test normally distributed has a mean of 600 and a standard
deviation of 60. What percet of test takers can expect to score between 540 and 680.? -
✔✔SO, you do X to Z to % for both numbers 540 and 680.
