More interpretations A household appliance manufacturer wants to analyze the relationship between total sales and the companys three primary means of advertising (television, magazines, and radio). All values were in millions of dollars. They found the regression equation Sales = 250 + 6.75 TV + 3.5 Radio + 2.3 Magazines. One of the interpretations below is correct. Which is it? Explain whats wrong with the others. a) If they did no advertising, their income would be $250 million. b) Every million dollars spent on radio makes sales increase $3.5 million, all other things being equal. c) Every million dollars spent on magazines increases TV spending $2.3 million. d) Sales increase on average about $6.75 million for each million spent on TV, after allowing for the effects of the other kinds of advertising.

Unit 9 Notes: Summary Statistics Week 8: 26 February 2018 Key Terms Key Terms 1. Mean: average 2. Mode: the biggest peak, the most common number (s) 3. Median: M, the middle number in the data set 4. Range: simply the distance between the max and the min points (max – min) 5. Standard deviation: how spread from the mean the data is 6. Variance: the standard deviation squared 7. Interquartile range: how spread out the middle 50% of the data is, calculated from the 5-number summary 8. Median and IQR: better for heavily skewed distributions or if you have outliers 9. Mean and Standard deviation: better for symmetric distributions without outliers How to describe the distribution