On the basis of data provided by a salary survey, the variance in annual salaries for seniors in public accounting firms is approximately 2.1 and the variance in annual salaries for managers in public accounting firms is approximately 12.1. the salary data were provided in thousands of dollars. assuming that the salary data were based on samples of 25 seniors and 26 managers, test to determine whether there is a significant difference between the variances of salaries for seniors and managers. at a 0.05 level of significance, what is your conclusion?

The wall street journal reported that walmart stores inc. is planning to lay off 2,300 employees at its sam's club warehouse unit. approximately half of the layoffs will be hourly employees (the wall street journal, january 25-26, 2014). suppose the following data represent the percentage of hourly employees laid off for 15 sam's club stores. 55 56 44 43 44 56 60 62 57 45 36 38 50 69 65 (a) compute the mean and median percentage of hourly employees being laid off at these stores. (b) compute the first and third quartiles. (c) compute the range and interquartile range. (d) compute the variance and standard deviation. (e) do the data contain any outliers? (f) based on the sample data, does it appear that walmart is meeting its goal for reducing the number of hourly employees?

Consider the following information on stocks a, b, c and their returns (in decimals) in each state: state prob. of state a b c boom 20% 0.27 0.22 0.16 good 45% 0.16 0.09 0.07 poor 25% 0.03 0 0.03 bust 10% -0.08 -0.04 -0.02 if your portfolio is invested 25% in a, 40% in b, and 35% in c, what is the standard deviation of the portfolio in percent? answer to two decimals, carry intermediate calcs. to at least four decimals.

Which of the following businesses is most likely to disrupt an existing industry? a. closer connex developed an earphone that receives emails and text messages and converts them to voice messages. the first models had poor reception, but they rapidly improved over time. b. mega technologies reconfigured the components used in its touchscreen tablets to create a new type of wearable device for use in restaurants and other service industries. c. particle inc. developed a teleportation technology that can transport physical materials instantaneously across great distances. d. altrea added advanced camera technology to its premium line of smartphones so that they would take the highest-quality photos of all phones on the market.