100(1 a)% confidence interval for the mean u of a normal population when the value of ở is known is given by Under the same conditions as those leading to the interval, (X - µ) Pl < 1.645- 0.95. Use this to derive a one-sided interval for u that has infinite width and provides a lower confidence bound on u. 1.645- Vn x + 1.645 Vn' ㅇ(-1.645% What is this interval for the true average porosity of a certain seam of coal samples that is normally distributed with true standard deviation 0.79 if the average porosity for 20 specimens from 4.85? (If you need to use co or -co, enter INFINITY or -INFINITY, respectively. Round your answers to four decimal places.)

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.