 Quandaries and Queries Hello, I am a Senior from Florida and I have a really hard general statistics class. I would like to know if you guys can help me with these two problems   I am having problems with these two questions:    Find the standard deviation of the given data set To get the best deal for CD dealer, Jessica called  eight appliance stores and asked the cast of a specific model. The prices she quoted are listed below.   \$300, \$203, \$272, \$332, \$440, \$119, \$129, \$254 Use the binomial probabilty formula to find the indicated probability. A company finds that an average  of 20% of all new employess resign during the first year. Find the probabilty that among the next 30  employess hired, exactly five resign  during the first year (n=30, x=5, p=5, = 0.2, q=0.8) Hi Urial, Here is a solution to the first problem. There are a number of equlvalent expressions for the variance V of a data set. The expression I find most useful is V = [n times (the sum of the squares of the x's) - (the sum of the x's squared)] all divided by n times (n-1) You have 8 observations so n = 8. The sum of the x's is 300 + 203 + ... + 254 = 2049 thus the sum of the x's squared is 20492 = 4198401 The sum of the squares of the x's is 3002 + 2032+ ... + 2542 = 604335 Hence the variance is V = (8 * 604335 - 4198401)/(8*7) = 11362.1 The standard deviation is the square root of the variance and hence standard deviation = Sqrt(11362.1) = \$106.59 Penny Go to Math Central