People with chronic pain often have trouble sleeping.  It turns out lack of sleep can make pain worse. University of California researchers had 25 adults come into their lab on two occasions: once after a full night’s sleep, and once after staying up all night. The two visits occurred at least a week apart, with the all-nighter randomly assigned for each subject to come before the first or second visit. On each visit, the subjects’ pain tolerance was measured using a small heated pad applied to their skin near the ankle.  This is an example of which study design?

Scientists have developed a new forensic method for estimating the age of an unidentified crime victim using DNA information in the victim’s blood. To confirm the accuracy of the method, Dutch researchers measured this variable along with the age of 195 volunteers ranging in age from a few weeks to 80 years. The resulting scatterplot (from their paper in Current Biology) is shown below.         The researchers put the blood test measure on the horizontal axis because they intend to use it as the explanatory variable to determine age (response variable). NOTE: this measure takes negative values. The least squares regression line is AGE = -33.65 – 6.74 x BLOOD TEST MEASURE with r-squared = 83.5%.  The researchers propose using the equation of the line to determine the age of crime victims from the blood test measure. Which of the following is the correct interpretation of the slope of the regression equation?

A small city is considering building a community swimming pool using public funds. The city planner will survey a random sample of residents to ascertain support.  If she takes her random sample from a list of the parents of school children in the city school district, her sample may not be representative of all the residents of the city, so it will suffer from which problem?

A statistics instructor creates a student survey to get to know her students.  She created the survey from questions students provided.  Select ALL graphs that could be used to summarize the following survey question:  Would you eat pineapple on pizza?

Existing data of biological attributes for alligators, such as snout length in inches and weight in pounds, can be used as indicators of restoration success in water quality. Suppose the weight is converted from pound to kilogram (1 kilogram  =  2.2 pounds approximately), the correlation  coefficient, r, between the height and length will

A Dairy Queen restaurant recorded daily high temperatures (in degrees Fahrenheit) and sales volume (in dollars) for a sample of days this summer. they found the correlation beteen the two variables to be 0.825. If they convert the temperatures to degrees Celsius, the new correlation will (degrees Celsius = 5/9 (degrees Fahrenheit – 32).

The following chart shows the percentages of injuries to females that received emergency room care, according to the place where the injury occurred, comparing 2005-2008 and 2011-2014. The percentages don’t add up to 100%, which means that not all locations fit one of these categories.                                    A large percentage of injuries occur at the home (inside or outside).   In 2011-2014, what percentage of injuries occurred at the home (inside or outside)? (Enter a numeric value only.  Do not include the percent notation (%).)  

The graph below shows marriage rates for women and men in the 50 U.S. states and the District of Columbia for 2014 (Source US Census Bureau). What is a plausible value for the correlation coefficient between marriage rates for US women and men in 2014?

A statistics instructor creates a student survey to get to know her students.  She created the survey from questions students provided.  Select ALL graphs that could be used to summarize the following survey question:  Would you eat pineapple on pizza?

The New England Journal of Medicine reported that people who suffer a cardiac arrest in public places like casinos have a higher survival rate than those who have a heart attack in a hospital.  Which one of the following is a valid interpretation of this finding?