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anonymous
 2 years ago
A simple random sample of 400 households is taken in a large city, and the number of cars in each sampled household is noted. The average number of cars in the sampled households is 1.8 and the SD is 1.3. Among the sampled households, 10% had no car.
PROBLEM 5
This problem is worth 1 point
An approximate 90% confidence interval for the average number of cars among households in the city goes from _____________________ to _______________________.
anonymous
 2 years ago
A simple random sample of 400 households is taken in a large city, and the number of cars in each sampled household is noted. The average number of cars in the sampled households is 1.8 and the SD is 1.3. Among the sampled households, 10% had no car. PROBLEM 5 This problem is worth 1 point An approximate 90% confidence interval for the average number of cars among households in the city goes from _____________________ to _______________________.

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ybarrap
 2 years ago
Best ResponseYou've already chosen the best response.0\[\mu \pm z\alpha\] you already have average and standard deviation, what is "z" corresponding to 90th confidence interval?

ybarrap
 2 years ago
Best ResponseYou've already chosen the best response.0The z that gives 90% confidence interval is 1.645: http://www.wolframalpha.com/input/?i=inverse+normal+z%3D1.645

ybarrap
 2 years ago
Best ResponseYou've already chosen the best response.0\[1.8\pm1.645*1.3\] \[Lower Range: 1.81.645*1.3\] \[Upper Range: 1.8+1.645*1.3\] Does this make sense?

anonymous
 2 years ago
Best ResponseYou've already chosen the best response.0@ybarrap What about this? An approximate 99% confidence interval for the percent of city households that have no car goes from _____________________% to ______________________%.

anonymous
 2 years ago
Best ResponseYou've already chosen the best response.0Confidence Interval For Proportions
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