Scatterplots Answers

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1
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Marta believes that the equation of the line of best fit for the scatterplot below is . Which statement best summarizes why Marta is likely incorrect?

Question illustration
A
Marta’s equation has a positive y-intercept, but the scatterplot suggests a negative y-intercept.
B
Marta’s equation has a positive y-intercept, but the scatterplot shows a negative correlation.
C
Marta’s equation has a negative slope, but the scatterplot suggests a negative y-intercept.
D
Marta’s equation has a negative slope, but the scatterplot shows a positive correlation.
2
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Which scatterplot has a correlation coefficient closest to r = 1?

A
Option
Option A
B
Option
Option B
C
Option
Option C
D
Option
Option D
3

For which data set is a linear regression most reasonable?

A
a set of nine data pairs with a correlation coefficient r = –0.4
B
a set of five data pairs with a correlation coefficient r = 0.3
C
a set of four data pairs with a correlation coefficient r = –0.8
D
a set of six data pairs with a correlation coefficient r = 0.6
4

For several years, Graham has gathered data on students who own a computer and on their performance on a typing-speed test. He creates the linear model y = 3.8x + 17.4 where y represents the typing speed, in words per minute, of a student and x represents the number of years the student has owned a computer. According to Graham’s model, what is the approximate speed of a student who has owned a computer for three years?

A
21 words/min
B
29 words/min
C
56 words/min
D
64 words/min
5

The line of best fit for the scatterplot below passes through which pair of points?

Question illustration
A
P and Q
B
S and T
C
R and Q
D
S and Q
6

Poloma believes that the equation of the line of best fit for the following scatterplot is . Which statement best summarizes why she must be wrong?

Question illustration
A
Poloma’s equation has a positive y-intercept, but the scatterplot has a negative correlation.
B
Poloma’s equation has a positive slope, but the scatterplot has a negative correlation.
C
Poloma’s equation has a negative y-intercept, but the scatterplot has a positive correlation.
D
Poloma’s equation has a negative slope, but the scatterplot has a positive correlation.
7

A sociologist recorded the estimated life expectancies of women born in Center City. Use the data from women born in 1970 and 2000 to create a linear model that predicts the life expectancy, in years, (y) of a female born in a given year (x). YearBornLife Expectancy(years)196066.1197067.6198070.1199071.9200074.0201075.9Which equation represents this linear model?

A
y = 0.213x – 352.7
B
y = 0.213x – 358.4
C
y = 4.695x – 9181.6
D
y = 4.695x – 9322.4
8

The scatterplot shows the number of home runs Mario hits during his first four seasons on the company softball team. If his output continues to follow the linear model, approximately how many home runs will Mario hit during his ninth season?

Question illustration
A
30 home runs
B
35 home runs
C
45 home runs
D
50 home runs
9

A scatterplot is used to display data for a runner where x is the number of miles run, and y is the time, in minutes, that it takes to run that distance. Which interpretation describes a line of best fit of y = 9.5x for the data in the scatterplot?

A
For each 1 minute, the runner ran 9.5 miles.
B
For each 9.5 minutes, the runner ran 1 mile.
C
The minimum distance with a recorded time is 9.5 miles.
D
The maximum distance with a recorded time is 9.5 miles.
10

The school’s guidance department compares the grade-point averages and standardized state test scores for 10 students in each grade. The table below shows the correlation coefficient for each data set.Grade LevelCorrelation Coefficient9th grade0.310th grade–0.111th grade0.212th grade–0.8For which data set(s) is a linear regression model reasonable?

A
9th grade and 11th grade data sets
B
10th grade data set
C
10th grade and 12th grade data sets
D
12th grade data set

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