**Questions: 1-10**

**Q1.**

A random sample of 89 observations produced a mean x = 25.7
and a standard deviation s=2.5.

**a. **Find a 95% confidence interval
for u.

**b. **Find a 90% confidence interval
for u.

**c. **Find a 99% confidence interval
for u.

**Q2.**

A company wants to test a randomly selected
sample of n water specimens and estimate the mean daily rate of pollution
produced by a mining operation. If the company wants a 95% confidence interval
estimate with a sampling error of 1.1 milligrams per liter (mg/L), how many
water specimens are required in the sample? Assume prior knowledge indicates
that pollution readings in water samples taken during a day are approximately
normally distributed with a standard deviation equal to 7 mg/L.

**Q3.**

Each child in a sample of 65 low income children
was administered a language and communication exam. The sentence complexity
scored had a mean of 7.61 and a standard deviation of 8.95. Complete parts a through
d.

**a. **From the sample, estimate the
true mean sentence complexity score of all low-income children.

**b. **Form a 90% confidence interval
for the estimate, part a

**c. **Give a practical explanation of
the interval, part b

**d. **Suppose the true mean sentence complexity
score of middle income children is known to be 15.55 is there evidence that the
true mean for low income children differs from 15.55.

**
Q4. Q5. Q6. ****Q7. Q8. Q9. Q10. **included in the file.