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# S1 ( Statistics ) Revision Questions Help watch

1. I have been given some data which includes 80 bottles of water and sigma x = 1028.0 and secondly sigma x^2 = 13064.80

The question says : " explain why your confidence interval provides strong evidence that the mean exceeds the highest acceptable value of 12.0 micrograms/litre ...
(2 marks)

I have calculated the mean to be 12.85 and variance to be 5 and confidence interval to be between 12.21 and 13.49 , but have no clue or understanding on how to write to phrase the answer or what would get 2 marks ...

Please Can Anyone Help Thanks ( appreciate it )
2. (Original post by Tha Realest)
I have been given some data which includes 80 bottles of water and sigma x = 1028.0 and secondly sigma x^2 = 13064.80

The question says : " explain why your confidence interval provides strong evidence that the mean exceeds the highest acceptable value of 12.0 micrograms/litre ...
(2 marks)

I have calculated the mean to be 12.85 and variance to be 5 and confidence interval to be between 12.21 and 13.49 , but have no clue or understanding on how to write to phrase the answer or what would get 2 marks ...

Please Can Anyone Help Thanks ( appreciate it )
If you've got a 95% confidence interval (which you probably have), then the probability that the true value of the mean is contained within that interval is 0.95. In other words, if you were to conduct the experiment 100 times, then the mean would lie in your interval 95 times.

So, given your interval, what can you say about the mean exceeding 12?
3. (Original post by Topmanfaz)
If you've got a 95% confidence interval (which you probably have), then the probability that the true value of the mean is contained within that interval is 0.95. In other words, if you were to conduct the experiment 100 times, then the mean would lie in your interval 95 times.

So, given your interval, what can you say about the mean exceeding 12?
Sorry forgot to say it is a 99% Confidence Interval ... So the mean would lie in the confidence interval 99 times , therefore it provides a strong evidence ?
4. (Original post by Tha Realest)
Sorry forgot to say it is a 99% Confidence Interval ... So the mean would lie in the confidence interval 99 times , therefore it provides a strong evidence ?
99 out of a 100 times, but yes, that's all you need to write. Make sure you mention that your interval is greater than 12.

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