What happens when network externalities are present? a. the usefulness of a product increases with the number of consumers who use it. b. the usefulness of a product decreases as the number of firms selling the product increases. c. the usefulness of networks diminishes with the number of consumers who enter them. d. the usefulness of telecommunications equipment rises?

One question from a survey was "how many credit cards do you currently have? " the results of the survey are provided. complete parts (a) through (g) below. click the icon to view the survey results. (a) determine the mean number of credit cards based on the raw data. the mean is 3.113.11 credit cards. (type an integer or a decimal. do not round.) (b) determine the standard deviation number of credit cards based on the raw data. the standard deviation is 1.9111.911 credit cards. (round to three decimal places as needed.) (c) determine a probability distribution for the random variable, x, the number of credit cards issued to an individual. x (# of cards) p(x) x (# of cards) p(x) 1 0.280.28 6 nothing 2 nothing 7 nothing 3 nothing 8 nothing 4 nothing 9 nothing 5 nothing 10 nothing (type integers or decimals. do not round.)

Adecision is made at the margin when each alternative considers

He interest rate effect is the change in real gdp caused by the federal reserve adjusting target interest rates. is the change in consumer and investment spending due to changes in interest rates resulting from changes in the aggregate price level. is the change in exports and imports, resulting from changes in the interest rate caused by changes in the aggregate price level. is the change in investment spending and government purchases caused by changes in money demand. is the change in interest rates, caused by changes to government purchases.