Answer:
Lower limit = 1007.95 cm/s
Upper limit = 1142.05 cm/s
Step-by-step explanation:
We have to calculate a 95% CI with population's standard deviation known.
The sample is size n=60, with mean M=1075.
The confidence interval can be expressed as:
![M-z*\sigma/\sqrt{n} \leq\mu\leq M+z*\sigma/\sqrt{n}](https://tex.z-dn.net/?f=M-z%2A%5Csigma%2F%5Csqrt%7Bn%7D%20%5Cleq%5Cmu%5Cleq%20M%2Bz%2A%5Csigma%2F%5Csqrt%7Bn%7D)
For a 95% CI, the value of z=1.96.
![1075-1.96*265/\sqrt{60} \leq\mu\leq 1075+1.96*265/\sqrt{60} \\\\1075-67.05 \leq\mu\leq 1075+67.05\\\\ 1007.95 \leq\mu\leq 1142.05](https://tex.z-dn.net/?f=1075-1.96%2A265%2F%5Csqrt%7B60%7D%20%5Cleq%5Cmu%5Cleq%201075%2B1.96%2A265%2F%5Csqrt%7B60%7D%20%5C%5C%5C%5C1075-67.05%20%5Cleq%5Cmu%5Cleq%201075%2B67.05%5C%5C%5C%5C%201007.95%20%5Cleq%5Cmu%5Cleq%201142.05)
Yes because if you turn 6 and three to 12 then you have 2/12 and 4/12!