A random sample of 130 students is chosen from a population of 4,500 students. If the mean IQ in the sample is 120 with a standard deviation of 5, what is the 99% confidence interval for the students' mean IQ score?

Question

anonymous · Answer

118.87−121.13

 107.12−132.88

 125−135

 115−125

anonymous · Answer

I currently have A as an answer  am i right ? @SolomonZelman  @cj49  @skullpatrol

amistre64 · Answer

you are going to need to determine a few things,  the standard error, and the zscore related to 99%

amistre64 · Answer

$$Z_{99\%}=\frac{x-\bar x}{SE}$$
$$Z_{99\%}=\frac{x-\bar x}{\sigma/\sqrt{n}}$$

anonymous · Answer

am A is correct right

amistre64 · Answer

$$2.576=\frac{CI-120}{5/\sqrt{130}}$$
$$120\pm 2.576(5)/\sqrt{130}=CI$$

amistre64 · Answer

http://www.wolframalpha.com/input/?i=120-2.576%285%29%2Fsqrt%28130%29 118.87 is the lower .. i like it