ballz

Question 1

the standard normal distribution

Answer 1

using the boundaries to find area: normalcdf(min, max, mean, SD)
using are to find boundary: invnorm(area to the left as a decimal, mean, SD) label each on the AP exam

Question 2

using normalcdf and invnorm
(calc tips)

Answer 2

the standard normal distribution is the normal distribution with mean and standard deviation. the normal table displays values for the standard normal distribution

Question 3

describing an association in a scatter plot

Answer 3

correlation measures the strength and direction of the linear relationship between x and y.
1. r is always between -1 and 1
2. close to 0 = very weak
3. close to 1 or -1 = very strong
4. exactly 1 or 1 = perfectly straight
5. positive r = positive correlation, negative r = negative correlation

Question 4

interpret r

Answer 4

address the following in context: direction, outliers, form, strength

Question 5

interpret LSRL slope “b”

Answer 5

when the x variable (context) is 0, the y variable (context) is predicted to be _______.

Question 6

interpret LSRL y-intercept “a”

Answer 6

for every 1 unit change in the x variable (context) the y variable (context) is predicted to increase/decrease by _____ units

Question 7

what is a residual?

Answer 7

if there is a leftover pattern in the residual plot, then the model used does not have the same from as the association

Question 8

interpreting a residual plot

Answer 8

residual = y-yhat (Actual - Predicted)
A residual measures the difference between the actual y value and the y value that is predicted by the LSRL

Question 9

interpreting LSRL “y hat”

Answer 9

using the LSRL to predict outside the domain of the explanatory variable (can lead to ridiculous conclusions if the observed association does not continue)

Question 10

extrapolation

Answer 10

y hat is the estimated or predicted y value for a given x value