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Math for Journalists

(Don’t be scared). Math for Journalists. Math for Journalists. Why do you need to know math? Budgets Reports Polls Studies. Math for Journalists. Knowing in your head isn’t enough. Need to know things so you can do them automatically.

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Math for Journalists

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  1. (Don’t be scared) Math for Journalists

  2. Math for Journalists • Why do you need to know math? • Budgets • Reports • Polls • Studies

  3. Math for Journalists • Knowing in your head isn’t enough. • Need to know things so you can do them automatically. • Examples: Pouring coffee; playing piano; running the Mountain Goat.

  4. Math for Journalists • Budgets: Numbers every budget story must have. • Total budget. • Last year’s total budget. • Percentage of change. • Breakdown of percentage of change (up or down) for key categories. • How much will taxes go up?

  5. Math for Journalists • These are often numbers government officials or nonprofit groups DO NOT want you to have? Why: Because they know people won’t like it if: • Officials just gave themselves a raise. • Taxes are going up. • Nonprofit is paying its president a lot. Can you think of other reasons?

  6. Math for Journalists • Figuring a percent. Budget is $10,000 Salaries take up $3,000 of the budget What percent do salaries take up? What do you do? Divide the part ($3,000) by the whole ($10,000). The result is the proportion? What’s proportion?

  7. Math for Journalists • Proportion is just a decimal version of a percentage …. • So: the answer to previous question is 0.3. • To turn into % just multiply by 100 • The answer is? Salaries make up 30 percentof the $10,000 budget.

  8. Math for Journalists Percentage of change • Last year the city budget was $8,000. • This year, it’s $10,000. • How much did it go up?

  9. Math for Journalists • Percentage means per hundred • So, a percentage is really just a fraction – something out of a hundred. • To get the percentage change, divide the difference between the two numbers by the starting number. So in our example: $10,000 • $8,000 • $2,000 $2,000/$8,000=0.25 0.25 X 100 = 25 percent

  10. Math for Journalists • So the budget went up 25 percent • When you know this (and lots more) you can • Ask Why • Figure out how last year’s increase compared to this year’s increase? Why is the jump so big? • You can question authoritatively when you know what you’re talking about Questions?

  11. Math for Journalists • Always include Percentage and raw numbers? WHY? • Imagine I’m the mayor, and I told you: • “I’m cutting taxes 100 percent?” • Would that mean more if taxes were $1 a year now or $10,000 a year now?

  12. Math for Journalists • What if the mayor says she is laying off only 2 percent of the city work force. • Would that be bad or good? • Would it matter if the city employed just 50 people? • What if the city employed 10,000 people in a community of 12,000 people? Raw numbers give context: Examples?

  13. Math for Journalists Polls Reports Studies Statistics • Journalists write about them all the time • But do they know what they are writing! • If they don’t, they can’t critically analyze

  14. Math for Journalists • Twenty Questions a Journalist Should ASK: • You all read this … what are some of them? • Why are they important? • Go over list.

  15. Math for Journalists Margin of Error ± 3% • First, what’s the difference between a sample and a Census? • What is margin of error based on? • How could it invalidate results in a political poll? Explain using French fries and potato chips

  16. Math for Journalists • Mean: (Average) … how to figure it. • Median (Midpoint) … how to figure it. Why does it matter? • Example: With our class

  17. Math for Journalists Statistical Significance • What does it mean? • First, what is it not. (Doesn’t mean study is important) • It’s a probability that the result you got didn’t happen by chance.

  18. Math for Journalists Correlation Vs. Causation • Not the same. • How are they different. • Ice cream and murder rate example. • Homer Simpson’s take

  19. Math for Journalists NACCRRA Study • Look it over? • What would you say about it? • Why did they compare child care costs to the parents’ median income? • Explain Pareto’s law. • Explain about professor who called you.

  20. Math for Journalists Twitter study • What isthe margin of error? • What do the charts in the study mean? • What iskind of misleading in the report?

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