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Sixty-two students were asked to complete a number puzzle. The number of minutes each student needed to complete the puzzle was recorded and the times are displayed in the histogram above. Which of the following describes the distribution?
The table above shows the regression output for predicting the number of calories from the number of milligrams of sodium for items at a fast-food chain. Which is a correct interpretation of the slope of the regression line?
A new fertilizer is to be tested on tomato plants to determine if it increases the production of the plants. The available land is divided into eight plots. Four of the plots are on a hill and four are in a valley as shown. The plots in the valley are expected to get more water due to the influence of gravity, and those on the hill will get more direct sunlight. A randomized block design will be used, using two blocks of four plots each. Which of the following blocking schemes would be most appropriate?
4. At a large hospital, the durations of emergency room visits, from check-in to discharge, are approximately normally distributed with a mean of 167 minutes and a standard deviation of 76 minutes. Which interval, to the nearest minute, contains the middle 80% of durations?
5. Aliana works 6-hour weekend shifts at an area chain restaurant as a hostess, and she wants to explore whether customer preferences are influenced by how you ask them about seating. Aliana's questioning strategy is as follows:
Aliana collected data over the course of several weekends, and her results are in the table below:
Which of the following is a true statement?
Biologists have two different methods for estimating the growth rate of a population of animals. One is based on counting the number of animals in a photographic image, and the other is based on a computer-calculated surface area of the animals in the image. (Larger animals are generally older and contribute more to reproduction.) The scatterplot above shows the estimates of the Population Growth Rate (PGR) for each method along with the line y= x. Which statement is true based on the scatterplot?
7. An infrared thermometer measures the surface temperature of an object from a distance. The measurement errors for one particular model are approximately normally distributed with a mean of 0 degrees C and a standard deviation of 1.3 degrees C. If the temperature of an object is 20 degrees C, what is the probability that the thermometer will report the temperature as less than 18 degrees C?
8. A study was conducted to test a new style of keyboard in preventing repetitive stress disorders. Volunteers who have had problems with such injuries were randomly assigned to use either a traditional keyboard or the new design. A significance test was conducted with the alternative hypothesis that a smaller proportion of those using the new keyboard will suffer injuries than those using the traditional keyboard. The resulting P-value was 0.07. Which is a correct interpretation of this P-value?
9. For a class project, Charlotte recorded the heights of all 28 students in her class and calculated several statistics. She then realized she made an error recording the height of the tallest person in the class. She correctly had him listed as the tallest, but needed to add two inches to his recorded height to correct it. Which of these measures of spread must remain unchanged?
10. A large company grants its hourly employees pay raises after their six-month performance review. The amounts of the raises average $0.25 per hour, with a standard deviation of $0.05 per hour. Let represent the average pay raise of 50 randomly selected hourly employees. Which calculation would give the approximate probability that is at least $0.30 per hour?