Thread: confidence interval

A sample of construction workers was taken in a large city.
16 of the 150 workers were unemployed.
I found the confidence interval of 6.5% to 14.8%.

the second part of the question...
The overall unemployment rate is 6.8%.
Based on your confidence interval, is there evidence at the 0.05 level to show that unemployment rate for city construction workers is significantly higher than the overall city rate.
What do I do?

Originally Posted by Morgan82

A sample of construction workers was taken in a large city.
16 of the 150 workers were unemployed.
I found the confidence interval of 6.5% to 14.8%. Mr F asks: Is this a 95% confidence interval? 90%? 99%?

the second part of the question...
The overall unemployment rate is 6.8%.
Based on your confidence interval, is there evidence at the 0.05 level to show that unemployment rate for city construction workers is significantly higher than the overall city rate.
What do I do?

I'll assume that you have calculated a 95% confidence interval. Does 6.8% lie in it? Your conclusion?

Originally Posted by mr fantastic

I'll assume that you have calculated a 95% confidence interval. Does 6.8% lie in it? Your conclusion?

Yes. 95% confident that its between 6.5% and 14.8%.
Yes, 6.8 is in there. But why does it say evidence at the 0.05 level?

Originally Posted by Morgan82

Yes. 95% confident that its between 6.5% and 14.8%.
Yes, 6.8 is in there. But why does it say evidence at the 0.05 level?

Evidence at the 0.05 level is using a 95% confidence interval.
Evidence at the 0.01 level would be a 99% confidence interval.
It's just a way of telling what confidence interval you should be using.