confidence interval is desired for the true average stray-load loss for a certain type of induction motor when the line current is held at 10 amps for a speed of 1500 rpm. Assume that the stray-load loss is normally distributed with a standard deviation of 3.0. Compute an 82% confidence interval when n=100 and the sample mean is 58.3. What is the lower value of this confidence interval?   How large must n be if the width of the 99% confidence interval is to be 1.0.

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.