Suppose the life of a particular brand of calculator battery is approximately normally distributed with a mean of 75 hours and a
standard deviation of 10 hours. If the manufacturer of the battery is able to reduce the standard deviation of battery life from 10 to 9 hours, what would be the probability that 16 batteries randomly sampled from the population will have a sample mean life of between 70 and 80 hours
Since the total measure of all the angles of a triangle is always 180, solve for x with the equation: 3x+1+2x-3+9x=180. x=13. Now plug in x and look for the smallest one, which will be B. 23 degrees.
