30. a businessweek/harris survey asked senior executives at large corporations their opinions about the economic outlook for the future. one question was, "do you think that there will be an increase in the number of full-time employees at your company over the next 12 months? " in the current survey, 220 of 400 executives answered yes, while in a previous year survey, 192 of 400 executives had answered yes. provide a 95% confidence interval estimate for the difference between the proportions at the two points in time. what is your interpretation of the interval estimate? anderson, david r.. essentials of statistics for business and economics (p. 472). south-western college pub. kindle edition.

Apiston-cylinder device contains 0.1 m3 of liquid water and 0.9 m3 of water vapor in equilibrium at 800 kpa. heat is transferred at constant pressure until the temperature of water reaches 350 °c. determine (a) the quality of water at the initial state (b) the work associated with this process, (c) the heat associated with this process.

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?

Acircular pipe of 30mm outside diameter is placed in an airstream at 30 c and latm pressure. the air moves in cross flow over the pipe at 20 m/s, while the outer surface of the pipe is maintained at 110 c. what is the drag force exerted on the pipe per unit length? what is the rate of heat transfer from the pipe per unit length?