AP Stats Chapter 3

What equation for the LSRL would be most reasonable for this data?

• $y=30.57+1.89x$
  

• $y=-26.16+1.58x$

• $y=-42.12-1.26x$
  

• $y=42.56-1.39x$
  

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CCSS.HSA.CED.A.2

CCSS.HSS.ID.B.6

CCSS.HSS.ID.C.7

The equation  $y=-26.16\ +\ 1.58x$   can be used to predict a student's heart rate after a brisk walk around the school, if their resting heart rate (before the walk) is known. Suppose a student's resting heart rate is 65 bpm, and after the walk their heart rate is 80 bpm.  What is the residual for this student?

• 76.54

• 3.46

• -3.46

• -76.54

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CCSS.HSA.REI.B.3

CCSS.HSA.SSE.A.1

The equation  $y=-26.16\ +\ 1.58x$   can be used to predict a student's heart rate after a brisk walk around the school, if their resting heart rate (before the walk) is known. Interpret the slope of the LSRL.

• A student's heartrate after the walk will be 1.58 times what their resting heartrate is. 

• If a student's resting heartrate increases 1 bpm, their heartrate after the walk is predicted to decrease 26.16 bpm

• If a student's resting heartrate increases 1 bpm, their heartrate after the walk is predicted to increase 1.58 bpm

• A student's heartrate before the walk is predicted to be 26.16 bpm lower than after the walk. 

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CCSS.HSS.ID.C.7

The correlation (r) between high school students' height (in inches) and weight (in pounds) for a large sample of students is found to be 0.3. If the weight measurements are converted to kg, what will be the resulting correlation?

(1 kg = 2.2 lbs)

• 0.3

• 0.66

• -0.3

• 0.136

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CCSS.HSS.ID.C.8

For a particular value of an explanatory variable, the residual is -0.7. Which of the following is a true statement?

• The regression line underestimates the actual response variable value at this point.

• The regression line overestimates the actual response variable value at this point.

• . A non-linear regression would provide a better fit.

• $r^2=0.49$

Data is obtained for a large group of college students relating the time they spent writing an essay and the grade on the essay. The equation is

grade = 30.18 + 6.49(time) with r = 0.724

What percentage of the variation in grades can be explained by looking at time spent on the essay?

• 52.4%

• 72.4%

• 27.6%

• 47.6%

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CCSS.HSS.ID.C.8

Interpret the circled point on this relative cumulative frequency graph.

• 60% of Starbucks drinks have 30g of sugar.

• 60% of Starbucks drinks have 30g of sugar or more.

• 60% of Starbucks drinks have 30g of sugar or less

• None of these interpretations is correct.

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CCSS.HSS.ID.A.1

Desiree is interested to see if students who consume more caffeine tend to study more as well. She randomly selects 20 students at her school and records their caffeine intake (mg) and the number of hours spent studying. What is the equation for the LSRL?

• Caffeine = 2.544 + 0.164(hours)

• Hours = 2.544 + 0.164(Caffeine)

• Caffeine = 0.164 + 2.544(hours)

• Hours = 0.164 + 2.544(Caffeine)

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CCSS.HSA.CED.A.2

CCSS.HSS.ID.B.6

CCSS.HSS.ID.C.7

Data was collected on the weight of a male  laboratory rat for the first 25 weeks after its birth. The linear regression equation is 
y= 40x+100, where x is number of weeks and y is weight in grams. 
What does the y-intercept mean in context of the problem?

• The predicted weight of the rat in year 0. 
• The predicted weight of the rat at birth. 
• The current weight of the rat. 
• The average increase in the rat's weight. 

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CCSS.HSS.ID.C.7

The linear regression equation is y = 61.93x - 1.79.  Use the equation to predict how far this person will travel after 10 hours of driving.

• 10 miles
• 617.5 miles
• 0.19 miles
• 500 miles

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CCSS.8.EE.C.8C