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.

An approximate 99% confidence interval for the percent of city households that have no car goes from _____________________% to ______________________%.

Question

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.

An approximate 99% confidence interval for the percent of city households that have no car goes from _____________________% to ______________________%.

anonymous · Answer

you have the interval from -2.575 to +2.575

anonymous · Answer

(this is not the answer).  in this interval you have the 99% of city households that have no car

anonymous · Answer

10% have no car, so =40

anonymous · Answer

I don't understand what you wrote... Let's see: if we go with 10% to the "SticiGui", we get -1.28, isn't it?

But the problem here now is that we are considering percent intervals, not value intervals. So how can we calculate them? (%1,%2)

anonymous · Answer

@asjara i do not know. I am thinking about... nice approach. 10% is -+ 0.126   Isnt it?

anonymous · Answer

1st part answer is 1.6934 to 1.9064.