An office supply company conducted a survey before marketing a new paper shredder designed for home use. In the survey, 87% of the people who used the shredder were satisfied with it. Because of this high acceptance right, the company decided to market the new shredder. Assume that 87% of all people who use it will be satisfied. On a certain day, 11 customers bought this shredder.  a) let x denote the number of customers in this sample of 11 customers who will be satisfied with this shredder. Find the mean and Standard deviation of x.  Mean=  SD=  b) find the probability that exactly 9 of the 11 customers will be satisfied  P(x=9) =

Definition Definition Measure of central tendency that is the average of a given data set. The mean value is evaluated as the quotient of the sum of all observations by the sample size. The mean, in contrast to a median, is affected by extreme values. Very large or very small values can distract the mean from the center of the data. Arithmetic mean: The most common type of mean is the arithmetic mean. It is evaluated using the formula: μ = 1 N ∑ i = 1 N x i Other types of means are the geometric mean, logarithmic mean, and harmonic mean. Geometric mean: The nth root of the product of n observations from a data set is defined as the geometric mean of the set: G = x 1 x 2 ... x n n Logarithmic mean: The difference of the natural logarithms of the two numbers, divided by the difference between the numbers is the logarithmic mean of the two numbers. The logarithmic mean is used particularly in heat transfer and mass transfer. ln x 2 − ln x 1 x 2 − x 1 Harmonic mean: The inverse of the arithmetic mean of the inverses of all the numbers in a data set is the harmonic mean of the data. 1 1 x 1 + 1 x 2 + ...