1. Psychologists want to estimate the mean attention time given to twins per week by their parents. A sample of 46 sets of twin boys is taken and the attention time given to them by their parents in a week is recorded. The results are a mean time of 22.08 hours with a standard deviation of 16.34 hours. Construct a 90% confidence interval for the population mean attention time given all twins. 2. A sample of 45 Charleston County households have a mean income of $21,633 with a standard deviation of $7,715, find a 95% confidence interval for the true population mean income for households in Charleston County. 3. Unoccupied seats on flights cause airlines to lose revenue. Suppose a large airline wants to estimate its average number of unoccupied seats per flight over the past year. To accomplish this, the records of 225 flights are randomly selected and the number of unoccupied seats is noted for each of the sampled flights. The sample mean is 11.6 seats and the standard deviation is 4.1 seats. Construct a 94% confidence interval for the population mean number of unoccupied seats per flight during the past year. 4. Microsoft wants to estimate the percentage of the population that regularly use Bing to perform internet searches. A random sample of 640 people revealed that 25 of them regularly use Bing. Construct a 99% confidence interval for the true population proportion of regular Bing users