Stats Midterm 1 Carmen Homework
bob wants to estimate the percentage of people who own a dog in his town, and he goes to all the apartment buildings to carry out his survey. He leaves out all the houses in town. What kind of bias is this?
Bias due to under coverage
what distribution can you compare to see if the corresponding two variables are related
conditional
the standard deviation
contains no units
if the mean of a data set is large, the standard deviation has to be large also
false
which of the following is the x variable in an experiment
independent variable, or factor
if you add 10 to every value of a data set, what happens to the standard deviation
it stays the same
summarizes the information from one variable only, without considering any information from another variable
marginal distribution
if data is skewed to the left
mean < median
if data is symmetric
mean = median
if data is skewed to the right
mean > median
suppose your data represent revenues from a group of 20 stores in a retail chain across the country, and revenue is measured in millions of dollars. the standard deviation would be measured in
millions of dollars
a five number summary contains what values
min, max, Q1, Q2, Q3
a flat histogram contains what kind of variability
more variability
mike marks down the gas mileage of his two cars every time he fills them up with gas for 6 months straight. at the end he notes that his mustang gets better mileage than his corvette.
observational study
what should the residual plot look like if the regression line fits the data well
points fall around the horizontal line y = 0, random patterns, no fan shapes
which kind of data would be appropriate to examine a scatterplot
quantitative data
the slices on a pie chart represent
relative frequencies
the average distance from the mean is measured by the
standard deviation
what is affected by skewness
standard deviation
what measure can never be negative
standard deviation
which summary measures cannot be directly calculated from a box plot
standard deviation, mean, sample size
when a difference in treatment is decided to be due to more than random chance, what do you call the results
statistically significant
what does SSE stand for
sum of squares for error
an outlier in a data set can significantly affect what value
the mean
if there are a few very small values in a data set compared to the rest of the data
the median will be larger than the mean
if two corresponding conditional distributions are different from each other in a two way table, we know that the
the variables are related
correlation is affected by outliers
true
you can have two data sets with the same mean but different standard deviations
true
which shows a strong linear relationship
value closest to 1 (positive or negative)
if residual is negative, then data point lies ____ regression line
below
which type of graph is best for comparing two or more quantitative data sets
box plot
which graph is made from the five number summary
boxplot
a two way relationship allows us to examine the relationship between what kind of variables
categorical
if residual is positive, then data point lies ____ regression line
above
a researcher is trying to use January temperatures to predict latitude
January temperature is the independent variable and latitude is the dependent variable
a listing of all possible values in a data set and how often they occurred is called
a data distribution
what kind of sample occurs when you put an ad in the newspaper and ask readers to take your survey
a self selected sample
what is the most common observational study
a survey
if variables a and b are related in a certain way in a two way table (with 2 variables), no matter how many other variables you look at in addition to these two, the relationship will
be changed (can be reversed due to Simpsons paradox)
