The Power of Data in the Media

The media are major users of data. One of the main purposes of the media is to inform the general public of general issues. However, the media may sometimes provide misleading or false impressions to sway the public or to increase ratings or circulation. And such, it is important to be able to understand and interpret how information is represented or misrepresented.

Ways the media misrepresents data:
  • Uses a catchy title
  • Sample size is too small
  • There is insufficient information
  • The sample is not representative
  • Changes the scale on the axes
  • Survey questions are unbiased
  • An inappropriate method to collect the data was used
  • Data are not reliable
/ Ways to display data properly:
  • Use the most appropriate type of graph
  • Use proper scales on the axes
  • Ensure sample size is appropriate
  • Use the most appropriate method to collect the data/use reliable data sources

To assess the strength/validity of a survey ask yourself the following questions.

  • Is the sample size large enough?
  • Is the sample representative?
  • Are the survey questions unbiased?
  • How was the data collected? Was the collection methodappropriate?
  • Are the data reliable?
  • Is there a possible bias in the person analyzing the data?
  • Is the correlation strong?
  • Is there any evidence to support a cause-and-effectrelationship?
  • Does the graph represent the data appropriately? Is the graphconstructed accurately?
  1. Example 1: The following graphs represent the number of cars and minivans sold in Canada over time. Based on the
  2. following graphs, which of the following statements is true? Justify your answer.

Car Sales Outpace Van Sales!

a) The sale of cars is increasing faster than the sale of minivans

b) There are more minivans sold than cars

c) If the current trends continue, eventually there will be more minivans sold than cars

d) The sale of minivans is increasing more slowly than the sale of cars

Example 2: The graphs in each pair show the same data. Choose the graph that displays the data more accurately. Justify your choice.

a)Canada’s population by age according to the 2001 census.

b)A company’s profits over a 5-year period.

Assessing How Data Were Collected and Graphed

Example 3: Four Grade 9 students collected data on school lunch preferences.

They concluded:

Is this conclusion valid?

Solution:

Was the sample size appropriate?

Was the sample representative?

Was the survey question biased?

How was the survey conducted?

Is the graph constructed accurately?

Assessing Assumptions About Cause and Effect

Example 4: A group of Grade 12 students performed a linear regression on data they collected from Statistics Canada

about the number of seniors and the number of weapons crimes in Canada.They concluded:

Is this conclusion valid?
Solution:

Was there bias in the data collected?

Is the graph constructed accurately?

Is the correlation strong?

Does the analysis support a cause-and-effect relationship?

E4.