Scatterplot

Describe the correlation coefficient if

r = 0.90

• Positive, weak

• Positive, strong

• Negative, weak

• Negative, strong

The police department tracked the number of ticket writers and number of tickets issued for the past 8 weeks.  The scatter plot shows the results.  Which statement is true?

• More ticket writers results in fewer tickets issued.

• There were 50 tickets issued every week.

• When there are 10 ticket writers, there will be 800 tickets issued.

• More ticket writers results in more tickets issued.

Mr. Thomas wanted to know if the amount of class time that he gave students to study affected their test scores.  What kind of relationship between class study time and test scores is shown on the scatter plot.

• No correlation

• Positive correlation

• Negative correlation

• Positive then negative correlation

The following scatter plot shows the weights and lengths of some dinosaurs.  Which statement accurately describes the information?

• The information shows a positive correlation.  The weight of a dinosaur tends to increase according to its length.

• The information shows a negative correlation.  the weight of a dinosaur tends to decrease according to its length.

• The information shows no correlation.  The weight and length vary according to the type of dinosaur.

• The information shows no correlation.  The relationship between the weight and length of a dinosaur is uncertain.

Which scatter plot show a positive relationship?

• Graph A

• Graph B

• Graph C

• Graph D

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books.  Use the trend line to predict how many chapters would be in a book with 180 pages. 

• 12 chapters

• 15 chapters

• 18 chapters

• 21 chapters

The scatter plot shows the number of absences in a week for classes of different sizes.  Trevor concluded that there is a positive correlation.  Which statement best describes why Trevor's conclusion was incorrect.

• The largest class does not have the most absences.

• The smallest class does not have the least number of absences.

• The data show no relationship between class size and number of absences.

• The data show a negative relationship between class size and number of absences.

This scatter plot shows the average traffic volume and average vehicle speed on a certain freeway for 50 days in 1999.  Which statement best describes this relationship.

• As traffic volume increases, vehicle speed increases.

• As traffic volume increases, vehicle speed decreases.

• As traffic volume increases, vehicle speed increases at first, then decreases.

• As traffic volume increases, vehicle speed decreases at first, then increases.

Ms. Ochoa recorded the age and shoe size of each student in her physical education class.  This graph shows her data.  Which of the following statements about the graph is true?

• The graph shows a positive trend.

• The graph shows a negative trend.

• The graph shows a constant trend.

• The graph shows no trend.

A group of friends recorded the time it took to ride their bikes around the park.  This scatter plot shows their results with the line of best fit.  Which is closest to the number of minutes it would take to complete 9 laps?

• 4

• 5

• 6

• 7