Directions: Use the 4-step process in determining the interval estimate. Problem: A sample of 60 Grade 9 students' ages was obtained to estimate the mean age of all Grade 9 students. Consider that X = 15.3 years and the population variance is 16. (Note: Standard Deviation is the square root of variance). Assume that the distribution is normal. Answer the following questions: 1. What is the point estimate for /? 2. Find the 95% confidence interval for 3. Find the 99% confidence interval for 4. What conclusions can you make based on each interval estimate ?The perimeter of interest is the population mean /, of the 1. Describe the population parameter of interest. TV viewing time of all 5-year old children. 2. Specify the confidence interval criteria. The sample of size 50 children is large enough for the a. Check the assumptions. Central Limit Theorem to hold. So, the sampling distribution of the means is normal. b. Determine the test statistic to be used to calculate the The statistic is the z, using o = 0.5 interval. c. State the level of confidence. 95% confidence level The sample information consists of: 3. Collect and present sample evidence = 3 ; n = 50 ; 0 =0.5 a. Collect the sample information. b. Find the Point Estimate The point estimate for the population mean is 3 hours (the sample mean) The confidence coefficient is 1.96 4. Determine the confidence Interval E= z () a. Determine the confidence coefficient. E= 1.96 ( 0.5 = 0.14 50 b. Find the maximum error E. Lower confidence limit: 3 - 0.14 = 2.86 Upper confidence limit: 3 + 0.14 = 3.14 c. Find the lower and the upper confidence limits. Interpretation: We can say with 95% confidence that the interval 2.86 d. Describe /interpret the results. hours and 3.14 hours contain the population mean / based on the 50 five-year old children's TV viewing time