)a photovoltaic array of (solar cells) is 10.0% efficient in gathering solar energy and converting it to electricity. if the average intensity of sunlight on one day is 700w/m2, what area should your array have to gather energy at the rate of 100 w? (b) what is the maximum cost of the array if it must pay for itself in two years of operation averaging 10.0 hours per day? assume that it earns money at the rate of 9.00 ¢ per kilowatt-

Onsider the following subscription behavior information from genie, a web site that provides tools for constructing a family tree (ancestor search). subscriptions cost $9.99 per month, but you are charged for the entire year at the time of purchase. there is a one-year minimum term when you sign up for the service. once purchased, subscriptions are set to renew automatically unless the subscriber cancels them. when a membership renews, it renews for a one-year term and again you are charged for the entire year. there are no variable costs associated with providing this service to an individual customer, but genie does engage in customer relationship activities that they believe will increase customer retention. these customer relationship activities cost genie about $10 per year per customer. based on a sample of 1000 customers that joined genie five years ago, near the time when the company was founded, they were able to determine how many of those customers remained subscribers in the second year, third year etc. based on this information, genie calculated the average annual retention rate to be 20%. genie uses an annual discount rate of 8%. a. last year, genie spent $10,000 placing advertisements on google. genie management believes that these advertisements were responsible for about 300 new subscribers. would you recommend to genie management that they purchase more google ads? b. suppose a newly-introduced loyalty program increases the number of customers that remained to 30%. does this new data change your answer to 9.a? c. do you have any hesitations or concerns about making recommendations to management based on your above estimate of customer lifetime value?

Rats that received electric shocks were unlikely to develop ulcers if the

True or false: a fitted model with more predictors will necessarily have a lower training set error than a model with fewer predictors.