A sample of size n = 44 has sample mean x = 54.3 and sample standard deviation s = 9.2. Part: 0 / 2 Part 1 of 2 Construct a 95% confidence interval for the population mean . Round the answers to one decimal place. A 95% confidence interval for the population mean is Sound it out: Phonics is an instructional method in which children are taught to connect sounds with letters or groups of letters. A sample of 137 first graders who were learning English were asked to identify as many letter sounds as possible in a period of one minute. The average number of letter sounds identified was 34.06 with a standard deviation of 23.64. Part: 0 / 2 Part 1 of 2 Construct a 95% interval for the mean number of letter sounds identified in one minute. Round the answers to two decimal places. A 95% confidence interval for the mean number of letter sounds identified in one minute is Use the Cumulative Normal Distribution Table to find the z-scores that bound the middle 70% of the area under the standard normal curve. Enter the answers in ascending order. Round the answers to two decimal places. The z-scores for the given area are and Lifetime of electronics: In a simple random sample of 100 electronic components produced by a certain method, the mean lifetime was 125 hours. Assume that component lifetimes are normally distributed with population standard deviation hours. Round the critical value to no less than three decimal places. - : 20 Part: 0/2 Part 1 of 2 (a) Construct a 95% confidence interval for the mean battery life. Round the answer to the nearest whole number. A 95% confidence interval for the mean battery life is