. A customer service representative must spend different amounts of time with each customer to resolve various concerns. The amount of time spent with each customer can be modeled by the following distribution:  X ~ Exp(0.4). Find  P(1 < x < 12).  (Round your answer to four decimal places.)

4c.) Draw the graphs. Round your final answers up to 6 decimal places, if applicable. Give the correct units.

Q2. A laundry for car wash found that the average, for small size car, cleaning time is 5 mins in the morning and 6.5 mins at evening time when a sample of size 30 is taken at the two time periods. From the previous record, the laundry manager knew that car oj = 2 mins for the morning shift and oz = 2.5 mins for morning and evening repectively. Find the interval estimate for 4 - 42 with 90% confidence level.

Harper collected data on students who make appointments to see their advisor to see how many failed to show up. The student records were divided into two groups: male (group 1) and female (group 2). A 93% confidnece interval for pi – P2 was found to be as follows: (0.03, 0.09) Interpret the endpoints of this interval in the context of this problem. Do not use the word "difference" in your answer.

The trade volume of a stock is the number of shares traded on a given day. The following data, in millions represent the volume of a certain stock traded for a random sample of 40 trading days in 2007. use the data to compute a point estimate for the population mean number of shares traded per day in 2007. (Round to three decimal places as needed.)

It is thought that prehistoric Indians did not take their best tools, pottery, and household items when they visited higher elevations for their summer camps. It is hypothesized that archaeological sites tend to lose their cultural identity and specific cultural affiliation as the elevation of the site increases. Let x be the elevation (in thousands of feet) for an archaeological site in the southwestern United States. Let y be the percentage of unidentified artifacts (no specific cultural affiliation) at a given elevation. Suppose that the following data were obtained for a collection of archaeological sites in New Mexico:  x 5.75 6.75 7.75 8.50 9.25 y 27 16 46 62 95 ​ What percentage of the variation in y cannot be explained by the corresponding variation in x and the least-squares line? Round your answer to the nearest tenth of a percent.    3.4%        18.4%        81.6%        9.7%