TOPIC: Confidence Interval When is unknown.

1. A sample of six college wrestlers had an average weight of 276 pounds with a sample standard deviation of 12 pounds. Find the 90% confidence interval of the true mean weight of all college wrestlers. If a coach claimed that the average weight of the wrestlers on the team was 310, would the claim be believable?
2. A recent study of 28 employees of XYZ company showed that the mean of the distance they traveled to work was 14.3 miles. The standard deviation of the sample mean was 2 miles. Find the 95% confidence interval of the true mean. If a manager wanted to be sure that most of his employees would not be late, how much time would he suggest they allow for the commute if the average speed were 30 miles per hour.
3. The number of unhealthy days based on the AQI (Air Quality Index) for a random sample of metropolitan areas is shown. Construct a 98% confidence interval based on the data.

61 12 6 40 27 38 93 5 13 40

PART 2

Hypothesis Testing

1. The average production of peanuts in Virginia is 3000 pounds per acre. Anew plant food has been developed and is tested on 60 individual plots of land. The mean yield with the new plant food is 3120 pounds of peanuts per acre, and the population standard deviation is 578 pounds. At = 0.05, can you conclude that the average production has increased?

INSTRUCTION:

1.Determine the null hypothesis 0 and alternative hypothesis

2. Identify the statistical test to be used, the value of , and the critical value of the test statistic.

3. Computation

4. Decision (reject or not to reject 0)

5. Conclusion (in non-technical terms)

2.The average salary for public school teachers for a specific year was reported to be P39,385. A random sample of 50 public school teachers in a particular city had a mean of P41,680, and the population standard deviation is P5975. Is there sufficient evidence at the = 0.05 level to conclude that the mean salary differs from P39,385?

INSTRUCTION:

1.Determine the null hypothesis 0 and alternative hypothesis

2. Identify the statistical test to be used, the value of , and the critical value of the test statistic.

3. Computation

4. Decision (reject or not to reject 0)

5. Conclusion (in non-technical terms)

3.The mean age of Senators in the 109th Congress was 60.35 years. A random sample of 40 senators from various state senates had an average age of 55.4 years, and the population standard deviation is 6.5 years. At = 0.05, is there sufficient evidence that state senators are on average younger than the Senators in Washington?

INSTRUCTION:

1.Determine the null hypothesis 0 and alternative hypothesis

2. Identify the statistical test to be used, the value of , and the critical value of the test statistic.

3. Computation

4. Decision (reject or not to reject 0)

5. Conclusion (in non-technical terms)