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wrote...
Posts: 249
2 weeks ago
Seatbelts Safety officials hope a public information campaign will increase the use of seatbelts above the current 70% level. Their efforts include running radio and TV ads, putting up billboards, having police officers appear on talk shows, and getting newspapers to indicate whether people injured in accidents were belted in. After several months they check the effectiveness of this campaign with a statewide survey of 560 randomly chosen drivers. 407 of those drivers report that they wear a seatbelt.

a. Verify that a Normal model is a good approximation for the binomial model in this situation.
b. Does the survey result suggest that the education/advertising campaign was effective? Explain.
Textbook 

Stats: Modeling the World


Edition: 4th
Authors:
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wrote...
2 weeks ago
a. np = 560(0.7) = 392, nq = 168; since both are at least 10 the sample is large enough
b. Use N(392, 10.84) to see z = 1.38. This is not an unusually high result, so the campaign may not have been effective.
wrote...
2 weeks ago
Brilliant
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