1. A financial analyst is interested in the percentage of revenue spent by computer software companies on research and development. A random sample of computer software companies is selected and the results are summarized in the following table:
(a) Calculate the mean, standard deviation and coefficient of variation.
(b) Estimate, from the frequency distribution table, the percentage of revenue spent on research and development is exceeded by 30% of computer software companies.
(c) Estimate, from the frequency distribution table, the proportion of computer software companies that spent between 7% and 10% of revenue on research and development.
(d) Construct a 99% confidence interval for the mean percentage of revenue spent by
all computer software companies on research and development. State your
assumption(s) and / or approximation(s).
2. (a) A marketing research company would like to form a new project team after employing a project manager. The project team will have 2 analysts and 4 fieldwork supervisors who are selected randomly from two existing project teams (team A and B) of this company. Team A has 3 analysts and 8 fieldwork supervisors and team B has 4 analysts and 9 fieldwork supervisors. What is the probability that equal number of analysts and fieldwork supervisors are selected from team A and team B?
(b) Every Friday morning Safety Security Ltd. delivers wages from a local bank to
each of 5 firms in a certain area. Having collected the necessary money from the
bank, a security van visits the 5 firms in turn but, as a precaution against robbery,
the same route is not used on each occasion. Immediately prior to each Friday’s
delivery, the van driver chooses at random, according to a procedure established
by the operations manager, the order in which the 5 firms will be visited.