Confidence intervals

[marintta]

So I have this problem and can't figure out how to find mean, when it's range is given. Help?

Exercise:
In order to study the effects of a new type of feed, the weight of 25 chickens is recorded after a certain life span. Based on the values obtained, it is concluded with 95% confidence that the mean weight of a chicken exceeds 300 g, but does not exceed 310 g. Assume that the weight of a chicken (in g) is a normally distributed random variable.
a) What is the mean and variance revealed by the sample of 25 chickens?
b) With a 99% confidence level, what can you conclude about the variance of a chicken's weight?

 

[Deleted member 4993]

So I have this problem and can't figure out how to find mean, when it's range is given. Help?

Exercise:
In order to study the effects of a new type of feed, the weight of 25 chickens is recorded after a certain life span. Based on the values obtained, it is concluded with 95% confidence that the mean weight of a chicken exceeds 300 g, but does not exceed 310 g. Assume that the weight of a chicken (in g) is a normally distributed random variable.
a) What is the mean and variance revealed by the sample of 25 chickens?
b) With a 99% confidence level, what can you conclude about the variance of a chicken's weight?

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:

READ BEFORE POSTING​

Please share your work/thoughts about this problem.

 

[Dr.Peterson]

So I have this problem and can't figure out how to find mean, when it's range is given. Help?

Exercise:
In order to study the effects of a new type of feed, the weight of 25 chickens is recorded after a certain life span. Based on the values obtained, it is concluded with 95% confidence that the mean weight of a chicken exceeds 300 g, but does not exceed 310 g. Assume that the weight of a chicken (in g) is a normally distributed random variable.
a) What is the mean and variance revealed by the sample of 25 chickens?
b) With a 99% confidence level, what can you conclude about the variance of a chicken's weight?

What you're given is a confidence interval. You need to work backward from that.

For example, if you knew the mean and standard deviation of the sample, how would you use them to find that confidence interval?