AP Stats Unit 2

2 Way Tables

100

True or False, a Mosaic Plot is only good for seeing conditional distributions.

False: A Mosaic Plot is good for seeing joint, marginal, and conditional distributions at the same time.

200

For a two way table, what does Marginal Relative Frequency measure?

Row or Column Totals (Row or Column Total/Total)

300

What does Conditional Relative Frequency Measure?

A single cell within a row or column, (cell/Row or Column total)

400

For a two way table, what does Joint Relative Frequency measure?

A single cell, (1 cell/total)

500

What type of variables do two way tables handle?

Two Categorical Variables.

Scatterplot

100

If r=1, is the scatter plot linear?

Yes

200

In a scatter plot where x=an individual's height, and y=an individuals weight, what does each point represent?

One person

300

In a scatter plot, which variable does the X axis usually represent?

explanatory variable

400

If a scatterplot has a weak negative correlation, what is the value of r?

Negative, but closer to zero (-.5)-(0)

500

What 5 things do you need to explain about a scatterplot on an FRQ?

CDOFS

Context - Provide context regarding the variables

Form – Linear, exponential, logarithmic, random, etc.

Direction – Positive or negative trend

Strength – Weak, moderate, strong (how close points fit a line)

Outliers – Deviations from pattern

LSRL

100

For this equation which letter depicts the Explanatory variable, and which letter depicts the predicted Response Variable? ŷ = a + bx

ŷ : predicted response variable

x : explanatory variable

200

Use your equation to predict what evaluation Mrs. H will get from a student who scored a 81. (Where x=student score)

ŷ = −29.27 + 1.338(x)

79.1

300

What does LSRL stand for?

Least Squares Regression Line

400

How do you interpret slope?

For every 1 unit increase in x, our y will change by the slope.

500

What is the equation used to find the slope using the data?

b = r (Sy/Sx)

Residuals

100

If the residual is positive, the observed point lies _____ the LSRL 

Above

200

Do we want there to be an obvious pattern in a Residual plot? ex) Fanning, curved

NO, if the residual plot has an obvious pattern, then the model we are using is not appropriate.

300

(True/False) The residual is the HORIZONTAL distance a data point is away from the LSRL.

False, The residual is the VERTICAL distance.

400

How do you calculate residual?

Residual = observed – predicted OR residual = y − ŷ

500

True or false: If you add up all the residuals from your data, you will get 0~

True

Calculator Commands

100

Does setting stat diagnostic to on allow you to find r?

Yes

200

How do you input data into a list?

Stat>1:Edit

300

How do you find the LSRL using a calculator?

Stat>Calc>8:LinReg(or 4:LinReg)

400

How do you create a scatter plot in your calculator?

1. Input data into list

2. Turn on stat plot, set graph to scatter plot

3. Set Xlist and YList to the lists you used

4. Press graph (use zoom 9 to fit scatter plot on screen)

500

How do you create a Residual plot using a Calculator?

1) Enter your x values in L1 and y values in L2

2) Perform a LinReg, either using 4:LinReg(ax + b) or 8:LinReg(a+bx)

3) Go to Stat Plot, XList is L1 and YList is RESID (get this by pressing 2nd → STAT → 9:RESID)

4) Zoom 9:Stat and you will have your plot!

5) Pressing “Trace” will give you the x-value and the corresponding residual value for “y”