Data Analysis (Chapter 1)
Variable that takes number values that are quantities--counts or measures.
What is quantitative variable?
The percent of values in a distribution that are less than the individual's data value.
What is percentile?
Variable that measures an outcome of a study.
Variable that helps predict or explain changes in a response variable.
What is response variable? What is explanatory variable ?
The entire group of individuals we information about in a study.
A subset of individuals in the population from which we collect data.
What is population and sample?
Definition says that if we observe more and more repetitions of any chance process, the proportion of times that a specific outcome occurs approaches its probability.
What is the Law of Large Numbers?
Information needed to describe the distribution of data in a histogram, dotplot, etc.. Acronym (S. O. C. S.) or (S. O. C. V.)
What is Shape, Outliers, Center, Spread (Variability)
Formula: (x - mean)/(standard deviation)
What is the z-score?
Observed y - predicted y
( y minus y-hat)
What is the residual?
Main difference between observational studies and experiments
What is a treatment?
Answers may vary.
Events that have no outcomes in common and can never occur simultaneously, for which the addition rule is used.
What are mutually exclusive events?
Standard deviation measures...
What is the typical distance of the values in a distribution from the mean?
Compare the mean and median in a normal distribution.
Mean=Median.
Interpret the slope in context of a least squares regression line.
when the explanatory variable increases by one unit, the response variable is predicted to increase/decrease by these many units.
Difference between a blind and double blind experiment
blind experiment only the individuals do not know
double blind neither the individuals nor the researchers know who gets the treatment or placebo.
Formula to check if events A and B are independent
P(A|B)=P(A) and P(B|A)=P(B)
What is the 5 number summary and list the names of the values...
Describes Distribution of quantitative data
Min
Q1
Median
Q3
Max
This rule helps to determine if data is normally distributed by checking the number of observation with each interval.
What is 68-95-99.7 rule?
Information needed to describe a scatter plot. (correlation)....4 Descriptions.
Direction
Outliers
Form
Strength
This experimental design involves the random assignment of units to treatments which are carried out separately with each group of units known to be similar in some way that is expected to affect the responses.
What is block design?
Find the probability that a randomly selected student in the room is wearing a sweatshirt, given that student is male.
P(sweatshirt given male)= P(sweatshirt and male)/P(male)
Describe how you can tell if a distribution if left skewed, right skewed, or symmetric using these two measures (mean and median)?
mean equals median it is symmetric
mean is higher than median then it is right skewed
mean is lower than median then it is left skewed
the mean follows the tail
Explain how to use table A to find area of normal distribution curve that is greater than a specific value when you are given the z score.
Using table A find the proportion of the given z-score. Since the table A given the proportions of the area to the left or less than, you would subtract the proportion from 1.
Measures the direction and strength of a linear relationship between two quantitative variables. (scatter plot)
What is the correlation (or r)?
Difference between random sampling and simple random sampling
Random sampling means every individual has an equal chance. Simple random sampling means every group and individual have an equal chance of being chosen as part of that group.
Find the Probability that the sum of two dice is greater than 8, given the sum is even.
What is .222?