11 Stat Questions Assignment | Buy Assignments Online

1. The table below shows the lengths of some randomly chosen CDs in John’s very large collection. Give the 95% confidence interval for the population mean, assuming that the population is approximately normally distributed. Round the endpoints to two decimal places.
71.3 60.6 50.8 60.1 47.3 65.2 56.8 36.9 43.7 43.3 5 1 3 5 8 9 8 2 9 4 55.7 64.5 74.1 55.0 40.9 49.9 48.0 43.8 36.7 60.9 6 1 4 5 9 8 8 6 6 6 37.0 47.9 47.0 48.7 56.8 72.9 55.0 67.7 51.2 43.3 7 2 4 6 8 6 7 5 6 9 52.4 42.4 71.3 3 4 6
Confidence interval: (
2.John measured the total playing time of 31 randomly chosen CDs from his very large collection and found a mean of 72.8 minutes and a standard deviation of 10.4 minutes. Give the 97% confidence interval for the population mean, assuming that the population is approximately normally distributed. Round the endpoints to two decimal places.
Confidence interval: (
3. Studies have suggusted that twins, in their early years, tend to have lower ‘Qs and pick up language more slowly than non-twins. The slower intellectual growth may be caused by benign parental neglect. Suppose it is desired to estimate the mean attention time given to twins per week by their parents. A sample of 35 sets of two-year-old twin boys was taken, and after one week the attention time received was recorded. The mean was found to be 29 hours with a standard deviation of 11.3 hours. Use this information to contruct a 93% confidence interval for the mean attention time given to all twin boys by their parents, assuming that the population is approximately normally distributed. Round the endpoints to one decimal place.