In this section, you will practice creating a scatterplot, and then using that scatterplot to analyze a relationship that exhibits a negative trend.

Use the ScatterPlot grapher by clicking the image below. The grapher will open in a new tab or window.

Click for additional directions on how to use the grapher.

1. The table below contains data describing different U.S. cities’ latitude (in degrees North from the equator) and the city’s average July high temperature.
   
   

   City	Latitude (°N)	Average July High Temperature (°F)
   Atlanta, Georgia	33.75	89
   Austin, Texas	30.25	96
   Baltimore, Maryland	39.3	87
   Birmingham, Alabama	33.5	91
   Boston, Massachusetts	42.6	81
   Buffalo, New York	43	80
   Charlotte, North Carolina	35.25	89
   Chicago, Illinois	41.8	84
   Cincinnati, Ohio	39	87
   Cleveland, Ohio	41.3	83
   Columbus, Ohio	40	85
   Dallas, Texas	32.75	96
   Denver, Colorado	39.75	88
   Detroit, Michigan	42.3	83
   Hartford, Connecticut	41.8	85
   Houston, Texas	30	94
   Indianapolis, Indiana	39.75	85
   Jacksonville, Florida	30.2	92
   Kansas City, Missouri	39	90
   Louisville, Kentucky	38.25	89
   Memphis, Tennessee	35.1	92
   Milwaukee, Wisconsin	43	80
   Minneapolis, Minnesota	45	83
   Nashville, Tennessee	36.2	89
   New Orleans, Louisiana	30	91
   New York, New York	40.8	84
   Oklahoma City, Oklahoma	35.5	94
   Orlando, Florida	28.5	92
   Philadelphia, Pennsylvania	40	87
   Pittsburgh, Pennsylvania	40.5	83
   Portland, Oregon	45.5	81
   Providence, Rhode Island	41.8	83
   Raleigh, North Carolina	35.75	90
   Richmond, Virginia	37.5	90
   Riverside, California	34	95
   Rochester, New York	43.2	81
   Sacramento, California	38.6	92
   Salt Lake City, Utah	40.75	93
   San Antonio, Texas	29.5	95
   San Jose, California	37.3	82
   Seattle, Washington	47.6	76
   St. Louis, Missouri	38.6	89
   Tampa, Florida	28	90
   Virginia Beach, Virginia	36.8	87
   Washington, DC	38.8	88


Click to see a popup table. From the table in the popup, copy the data from the Latitude (°N) column and Average July High Temperature (°F) column. Paste the data into the Data box of the grapher.

Latitude (°N)	Average July High Temperature (°F)
33.75	89
30.25	96
39.3	87
33.5	91
42.6	81
43	80
35.25	89
41.8	84
39	87
41.3	83
40	85
32.75	96
39.75	88
42.3	83
41.8	85
30	94
39.75	85
30.2	92
39	90
38.25	89
35.1	92
43	80
45	83
36.2	89
30	91
40.8	84
35.5	94
28.5	92
40	87
40.5	83
45.5	81
41.8	83
35.75	90
37.5	90
34	95
43.2	81
38.6	92
40.75	93
29.5	95
37.3	82
47.6	76
38.6	89
28	90
36.8	87
38.8	88


2. In the grapher, use the radio buttons to turn on the light grid lines and change the plot type to Scatter.
   
   
   
3. Click the Plot/Update button to generate a scatterplot. Use the scatterplot to answer the questions below.
   
   Interactive popup. Assistance may be required.

   See a sample graph

   

• Do the data points appear to follow a linear trend? How can you tell?
  Interactive popup. Assistance may be required.
  

  Check Your Answer

  Yes. Even though you cannot connect all of the data points with one line, all of the data points lie clustered near a line. Interactive popup. Assistance may be required.

• As you read the graph from left to right, do the points seem to move upward or downward? Interactive popup. Assistance may be required.
  
  

  Check Your Answer

  The points move downward as you read the graph to the right.

• As the latitude of the city increases, what happens to the city’s average July high temperature?
  
  Interactive popup. Assistance may be required.

  Hint

  The latitude of each city is plotted along the horizontal axis, and the average July high temperature of each city is plotted the vertical axis. The values along the horizontal axis increase from left to right and the values along the vertical axis increase from bottom to top. Interactive popup. Assistance may be required.

  Check Your Answer

  As the latitude of the city increases, the city’s average July high temperature decreases.
• If a randomly chosen city has greater latitude, what can you predict will be that city’s average July high temperature? Interactive popup. Assistance may be required.
  
  

  Hint

  Use your answer from the previous question to help you. A city with greater latitude is indicated by a point farther to the right along the horizontal axis. Interactive popup. Assistance may be required.

  Check Your Answer

  If a randomly chosen city has greater latitude, then that city's average July high temperature will be lower.
• Do you think that there is a cause-and-effect relationship between the latitude of a city and that city's average July high temperature? Explain your answer.
  
  Interactive popup. Assistance may be required.

  See a Possible Answer

  Yes, there could be. A city with a greater (higher) latitude is farther north, and cities that are farther north are typically cooler than cities that are farther south.