Determine whether the study depicts an observational study or an experiment.A medical researcher obtains a sample of adults suffering from diabetes. She randomly assigns 82 people to a treatment group and 82 to a placebo group. The treatment group receives a medication over a period of three months and the placebo group receives a placebo over the same time frame. At the end of three months the patients’ symptoms are evaluated.

Provide an appropriate response.When results from a scholastic assessment test are sent to test-takers, the percentiles associated with their scores are also given. Suppose a test-taker scored at the 88th percentile for their verbal grade and at the  percentile for their quantitative grade. Interpret these results.

Provide an appropriate response.Use the following frequency distribution to determine the class limits of the third class.

Provide an appropriate response.The February utility bills (in dollars) for ten residents of a large city are listed below. Find the mode amount. 

Provide an appropriate response.The commuting times of ten employees (in minutes) are listed below. Find the mode score. 

Provide an appropriate response.The grades are given for a student for a particular term. Find the grade point average. The point values of grades are given below.A : 4,B : 3,C : 2,D : 1,F : 0  C4  A1  F3  B2  A4

Provide an appropriate response.Retailers are always interested in determining why a customer selected their store to make a purchase. A sporting goods retailer conducted a customer survey to determine why its customers shopped at the store. The results are shown below. Find the percentage of the customers responded that the merchandise was the reason they shopped at the store. Round to the nearest whole percent.

Provide an appropriate response.The city council of a small town needs to determine if the townʹs residents will support the building of a new library. The council decides to conduct a survey of a sample of the townʹs residents. Which one of the following procedures would be least appropriate for obtaining a sample of the townʹs residents?

Provide an appropriate response.At a tennis tournament a statistician keeps track of every serve. The statistician reported that the mean serve speed of a particular player was 95 miles per hour (mph) and the standard deviation of the serve speeds was 10 mph. Assume that the statistician also gave us the information that the distribution of the serve speeds was bell shaped. What proportion of the player’s serves are expected to be between 105 mph and 125 mph?

Provide an appropriate response.A television station claims that the amount of advertising per hour of broadcast time has an average of 13 minutes and a standard deviation equal to 1.1 minutes. You watch the station for 1 hour, at a randomly selected time, and carefully observe that the amount of advertising time is equal to 14 minutes. Calculate the z-score for this amount of advertising time.