Friday

September 19, 2014

September 19, 2014

Posted by **Keirson** on Thursday, October 11, 2007 at 7:26pm.

1) construct a 95% confidence interval for the mean number of colonies

2) after constructing the interval above, the resarcher notices that it is quite wide, and wishes to do a follow-up study with greater precision. How large a sample is reuired to produce a 95% confidence interval with margin of error 5?

IM SO CONFUSED!!

- STATISTICS -
**MathGuru**, Friday, October 12, 2007 at 12:50amSince your sample size is small and the problem doesn't say that the population has a normal distribution, you may want to use a t-table to determine the 95% confidence interval. A general example of a formula is: CI95 = mean + or - (t-value)(sd/√n)

Note: sd = standard deviation.

You will need to determine mean and standard deviation before you can plug the values into the formula to determine the interval. The sample size is 6.

For the second part, you will need a formula to determine sample size. There are different formulas you can use; here is an example: n = [(t-value) * sd)/E]^2

Note: E = 5

I hope this will help.

- STATISTICS -
**MathGuru**, Friday, October 12, 2007 at 12:59amOne other comment: if you are expected to use a z-value instead of a t-value, the z-value would be 1.96 using a z-table for a normal distribution.

**Answer this Question**

**Related Questions**

.. - are most petri dishes the same size? if so what would the diameter of one ...

science - are most petri dishes the same size? if so what would the diameter of ...

Science - Table 1: Results of F1 Cross Observed Phenotypes of F2 Progeny # green...

bio - Determine the number of colonies counted on the LB plate in the following ...

PreCalculus - 2000(1 – 0.75) = 2000 (.25) = 500 survivors after the dose of ...

statistics - Suppose a study is done in which several random samples of people ...

Statistics - If many random samples of 64 students who took the second midterm ...

Chemistry - Two samples of water of equal volume are put into two dishes and ...

maths - a number which is less than or equal to 150 but if counted in pairs, one...

math - A certain antibioyic reducesthe number of bacteria in your body by 10% ...