For tasks 7-12, assume that the time interval between customers entering your store can be modeled using an exponential distribution. you know that you have an average of 4 customers per minute, so the rate is 4, or you can say that lambda = 4 according to yakir (2011, p. 79-80).

it is easiest to keep everything in the original units of measurement (minutes), but you can also translate that to seconds because a rate of "4 customers per minute" is the same as "4 customer per 60 seconds," and you can divide each number by 4 to get a rate of "1 customer per 15 seconds" or a rate of "1/15 customers per second."

7) what is the expectation for the time interval between customers entering the store? be sure to specify the units of measurement in your answer (see yakir, 2011, pp. 79-80). round to 3 decimal places:

8) what is the variance of the the time interval? be sure to specify the units of measurement in your answer. round to 3 decimal places:

9) the pexp() function is introduced at the bottom of yakir, 2011, p. 79, and there are some tips above. what is the probability that the time interval between customers entering the store will be less than 15.5 seconds. be sure to enter values so that everything is in the same unit of measurement. be sure to specify the units of measurement in your answer. round your answer to 3 decimal places:

10) what is the probability that the time interval between customers entering the store will be between 10.7 seconds and 40.2 seconds (see yakir (2011, p. 79-

11) the qexp() function in r allows you to enter a probability, and it will tell you the criterion value ("cutoff point") that corresponds to that probability value (e. g., if you enter .05 it tells you the cutoff point below which 5% of the values in the distribution fall).

what value of x would be the criterion value (cut-off point) for the top 5% of time intervals (round to 3 decimal places, and include the units of measurement)?



12) describe in your own words the meaning of the number that the following r command produces (you are asked to interpret the resulting number so that we understand what that number means).

Part a what is the area of triangle i? show your calculation. part b triangles i and ii are congruent (of the same size and shape). what is the total area of triangles i and ii? show your calculation. part c what is the area of rectangle i? show your calculation. part d what is the area of rectangle ii? show your calculation. part e rectangles i and iii have the same size and shape. what is the total area of rectangles i and iii? show your calculation. part f what is the total area of all the rectangles? show your calculation. part g what areas do you need to know to find the surface area of the prism? part h what is the surface area of the prism? show your calculation. part i read this statement: “if you multiply the area of one rectangle in the figure by 3, you’ll get the total area of the rectangles.” is this statement true or false? why? part j read this statement: “if you multiply the area of one triangle in the figure by 2, you’ll get the total area of the triangles.” is this statement true or false? why?

2/3(-6y+9x) expand each expression using the distributive property

Jobs and productivity! how do retail stores rate? one way to answer this question is to examine annual profits per employee. the following data give annual profits per employee (in units of 1 thousand dollars per employee) for companies in retail sales. assume σ ≈ 4.0 thousand dollars. 3.7 6.7 3.6 8.5 7.5 5.9 8.7 6.4 2.6 2.9 8.1 −1.9 11.9 8.2 6.4 4.7 5.5 4.8 3.0 4.3 −6.0 1.5 2.9 4.8 −1.7 9.4 5.5 5.8 4.7 6.2 15.0 4.1 3.7 5.1 4.2 (a) use a calculator or appropriate computer software to find x for the preceding data. (round your answer to two decimal places.) thousand dollars per employee (b) let us say that the preceding data are representative of the entire sector of retail sales companies. find an 80% confidence interval for μ, the average annual profit per employee for retail sales. (round your answers to two decimal places.) lower limit -- thousand dollars upper limit -- thousand dollars (c) let us say that you are the manager of a retail store with a large number of employees. suppose the annual profits are less than 3 thousand dollars per employee. do you think this might be low compared with other retail stores? explain by referring to the confidence interval you computed in part (b). yes. this confidence interval suggests that the profits per employee are less than those of other retail stores. no. this confidence interval suggests that the profits per employee do not differ from those of other retail stores. correct: your answer is correct. (d) suppose the annual profits are more than 6.5 thousand dollars per employee. as store manager, would you feel somewhat better? explain by referring to the confidence interval you computed in part (b). yes. this confidence interval suggests that the profits per employee are greater than those of other retail stores. no. this confidence interval suggests that the profits per employee do not differ from those of other retail stores. (e) find an 95% confidence interval for μ, the average annual profit per employee for retail sales. (round your answers to two decimal places.) lower limit 3.75 incorrect: your answer is incorrect. thousand dollars upper limit 6.41 incorrect: your answer is incorrect. thousand dollars