Scatter Plots
The type of association shown when points on a scatter plot go up from left to right.
positive correlation
A correlation coefficient close to 0 indicates this type of relationship.
no correlation
The equation form used for a line of best fit.
y=mx+b
If the data shows that as one variable increases, the other decreases, this is called this type of correlation.
negative correlation
A survey of 100 students asked if they like pizza and/or burgers. The results are shown in a two way table. 60 students like pizza, 50 like burgers, and 30 like both. How many students like neither pizza nor burgers?
20
What you can say about the relationship if the points on a scatter plot are widely scattered and show no pattern.
no correlation
The correlation coefficient for a perfect negative linear relationship.
-1
If the line of best fit for data is y = 2x + 3, what is the predicted y-value when x = 4?
11
The difference between an observed value and its predicted value from the line of best fit.
residual
In a class, 25 students play basketball, 18 play soccer, and 10 play both. How many students play only basketball?
15
The variable that is usually plotted on the x-axis in a scatter plot.
independent variable
If the correlation coefficient is 0.85, describe the strength and direction of the relationship.
strong positive correlation
Which of the following statements is true about a line of best fit?
C. It minimizes the distance between itself and all the data points.
If a data set shows that as the number of absences increases, the final grade decreases, what is the correlation?
C Negative Correlation
A group of 40 people were surveyed about their pets. 22 have cats, 16 have dogs, and 8 have both. How many people have only dogs?
8
The term for a data point that does not fit the overall pattern of a scatter plot
outlier
This is the range of possible values for the correlation coefficient, r.
If a scatter plot shows a downward trend, what can you say about the slope of its line of best fit?
a. The slope is negative.
If the points on a scatter plot are widely spread and do not show any clear pattern, what does this indicate about the variables?
b. There is no correlation between the variables
A two way table shows that 12 students like math, 15 like science, and 5 like both. How many students like only science?
10
What is the main purpose of a scatter plot ?
To show the relationship between two variables.
-0.95
0.05
0.5
0.3
-0.95
A line of best fit for a set of data is y = 3x + 1. What is the predicted value of y when x = 2?
Which statistic measures the strength and direction of a linear relationship between two variables?
c. Correlation coefficient
In a survey, 80 people were asked if they like tea or coffee. 45 like tea, 55 like coffee, and 20 like both. How many people like only tea?
25