The cost of a kilowatt hour of energy in the bill is 0.20 euros. A cylindrical led bulb of 5 W has a luminous flux of 50 lm. What is the luminous efficiency of this light source? Knowing that the bulb is 5cm long, 36mm in diameter, and plugged into a 220V socket, what is the resistivity of the bulb? How much would you spend in a year if you used 5 LED bulbs all on for 12 hours a day?

7. see worksheet 1 for values of variables x1, x2 and x3 and answer the following questions: a. for each variable find the mean, median, coefficient of skewness, range and population standard deviation. b. compared to variable x1, how are the mean and median affected by extreme values (outliers) seen in x2 and x3. c. is the median or mean the better measure of location for x2 and x3? explain. d. explain the differences in the magnitudes of the skewness coefficients for the three variables. e. what is the relationship between the range and standard deviation looking across the three variables?