Unit Quiz 1 Flashcards
Identifiers of shape
Uní modal, bimodal
Right skewed, left skewed
Likely outliers
Mean = median
Symmetric
Mean > median
Right skewed
Mean< median
Left skewed
How to Identify outliers
Q1 -(1.5 * IQR)
Q3+(1.5*1QR)
Center
Identify mean which si absolute value bar over x
Identify median, midpoint of all observations
Spread
IQR: Q3-Q1
Standard deviation: avg distance away from the mean
What does SOCS stand for
Shape outlier centers spread
Histogram
Quantitative data, bars side by side
Use percents!
Bar graph
Categorical data, bars have space in between
Use counts of qualitative data
Individuals
Objects describes by a set of data(people, things, etc)
Frequency table
Displays counts
Relative frequency table
Shows percents
Association
Knowing the value of one variable helps predict the other, mo association is graphs looks the same
Mode
The most common value
Skewed to the right
More data in left
Skewed to the left
More data on right
What to do when making stemplot
Always make a key!
When to use back to back stemplot
To compare 2 categorical variables
How to find center or midpoint of histogram
Look for the value in the middle of your categorical variables
How are dotplots stemplot and histogram similar
They all use quantitative variables
Range
Difference of largest and smallest value in data
Resistance
Mean is not resistant
Median is resistant
How are outliers identified in box plots
Data point identified outside the whiskers of the box plot, first found with 1.5*IQR rule
Variance
The average squared deviation
Steps to find standard deviation
Step 1: Find the mean.
Step 2: For each data point, find the square of its distance to the mean.
Step 3: Sum the values from Step 2.
Step 4: Divide by the number of data points.
Step 5: Take the square root.
Is standard deviation ever less than zero
No it is always greater than or equal to 0
It equals zero When all observations have the same value
Is standard deviation resistant
No
4 step process
State: what’s the question you’re trying to answer
Plan: how will you go about answering the question? What statistical techniques does this problem call for?
Do: make graphs and carry out needed calculations
Conclude: give your conclusions in the setting of the real world problem
Marginal distribution
Look at the margins of the table(in 2 way look far right at totals)
Can be represented as counts or percentage
Conditional distribution
Based on the colum or row that condition is based on, strictly circle and focus that whole column and row and base your percentages from that total
Based on percentages
Determine if marginal or conditional distribution:
Distribution fo % correct
Marginal
So you will use the total total value
And it can be % or counts
Use margins
Determine if marginal or conditional distribution:
% of males in sample own their homes?
Conditional distribution
Only use percents
Use that on column(or row)that the condition is based off of!
Determine if marginal or conditional distribution:
Distribution of scored among those who studied greater than 60 mins
Conditional distribution
Use percents
Only use that column(or row)!
when do u use median and IQR vs mean and standard deviation
If the distribution is symmetric, then use the Mean & Standard Deviation. Otherwise If the distribution is skewed, then use the Median & IQR becuase exit is resistant
Histogram bib width of 5
5 goes in the next bar
1st bar has 0,1,2,3,4
