For 15 delivery drones, a least-squares line predicts battery used, in percent, from distance flown, in kilometers: $\hat{y}=3.2+0.18x$. Predict battery used for 40 km.

A line for 12 school bus routes predicts fuel used, in liters, from route length, in kilometers: $\hat{y}=4.5+0.32x$. What is the predicted fuel use for a 25 km route?

For 10 bean plants, a regression line predicts height, in centimeters, from fertilizer, in grams: $\hat{y}=12.0+1.8x$. Predict the height when a plant gets 5 grams of fertilizer.

A swim team model predicts lap time, in seconds, from weeks of practice: $\hat{y}=62.0-1.4x$. What lap time is predicted after 8 weeks of practice?

For bakery dough, a line predicts rise, in centimeters, from oven temperature, in degrees Celsius: $\hat{y}=1.5+0.22x$. Predict the rise at 30 °C.

A clinic model predicts waiting time, in minutes, from the number of patients ahead: $\hat{y}=4.0+6.5x$. What wait is predicted when 3 patients are ahead?

For 11 farm plots, a line predicts crop yield, in kilograms per plot, from rainfall, in centimeters: $\hat{y}=18.0+2.4x$. Predict yield after 7 cm of rainfall.

A bike rental shop predicts daily income, in dollars, from rental hours: $\hat{y}=15+8x$. What income is predicted for 6 rental hours?

A class model predicts quiz score, in points, from hours studied: $\hat{y}=52+7.5x$. What score is predicted for 4 hours of studying?

A track meet model predicts water used, in liters, from the number of runners: $\hat{y}=6.0+0.75x$. Predict water used for 20 runners.

For 11 backpacks, contents have $\bar{x}=3.0$ kg and $s_x=0.8$ kg; strap stretch has $\bar{y}=7.2$ cm and $s_y=1.6$ cm; $r=0.75$. Find the slope predicting stretch from contents.

For 10 farms, nitrogen has $\bar{x}=1.8$ g/kg and $s_x=0.5$ g/kg; yield has $\bar{y}=6.0$ kg/m² and $s_y=1.2$ kg/m²; $r=0.60$. Find the slope predicting yield from nitrogen.

For 14 swimmers, practice time has $\bar{x}=6$ hours and $s_x=3$ hours; laps completed has $\bar{y}=42$ laps and $s_y=6$ laps; $r=0.70$. Find the slope predicting laps from practice time.

For 9 classrooms, noise has $\bar{x}=58$ decibels and $s_x=5$ decibels; task time has $\bar{y}=24$ minutes and $s_y=4$ minutes; $r=0.65$. Find the slope predicting task time from noise.

For 12 weather stations, temperature has $\bar{x}=23$ °C and $s_x=4$ °C; ice cream sales have $\bar{y}=150$ liters and $s_y=20$ liters; $r=0.90$. Find the slope predicting sales from temperature.

For 8 phone models, screen size has $\bar{x}=14.0$ cm and $s_x=1.5$ cm; battery capacity has $\bar{y}=18.0$ Wh and $s_y=6.0$ Wh; $r=0.70$. Find the slope predicting capacity from screen size.

For 16 students, sleep has $\bar{x}=7.0$ hours and $s_x=1.2$ hours; reaction time has $\bar{y}=310$ ms and $s_y=30$ ms; $r=-0.60$. Find the slope predicting reaction time from sleep.

For 13 gardens, sunlight has $\bar{x}=7.5$ hours and $s_x=1.6$ hours; tomato mass has $\bar{y}=5.0$ kg and $s_y=2.4$ kg; $r=0.50$. Find the slope predicting tomato mass from sunlight.

For 10 printers, speed has $\bar{x}=18$ pages per minute and $s_x=4$; price has $\bar{y}=210$ dollars and $s_y=40$ dollars; $r=0.60$. Find the slope predicting price from speed.

For 9 aquariums, water temperature has $\bar{x}=24$ °C and $s_x=2$ °C; fish activity has $\bar{y}=30$ counts/min and $s_y=8$ counts/min; $r=0.75$. Find the slope predicting activity from temperature.

For 12 museums, visitors have $\bar{x}=20$ hundreds of visitors, sales have $\bar{y}=14$ thousand dollars, and the slope is 0.45 thousand dollars per hundred visitors. Find the y-intercept.

For 10 greenhouses, temperature has $\bar{x}=24$ °C, plant height has $\bar{y}=60$ cm, and the least-squares slope is 1.8 centimeters per degree Celsius. Find the y-intercept.

For 14 fitness classes, weekly classes have $\bar{x}=8$, attendance has $\bar{y}=120$ people, and the slope predicting attendance from weekly classes is 9.5 people per class. Find the y-intercept.

For 15 cafés, temperature has $\bar{x}=22$ °C, cold drinks sold have $\bar{y}=110$ drinks, and the slope is 3.0 drinks per degree Celsius. Find the y-intercept of the line.

For 9 clinics, nurses on shift have $\bar{x}=5$, patients served have $\bar{y}=68$, and the regression slope is 11 patients per nurse. Find the y-intercept.

For 11 libraries, hours open have $\bar{x}=9$, books checked out have $\bar{y}=180$, and the slope is 14 books per hour. Find the y-intercept.

A regression line predicts monthly electricity use, in kilowatt-hours, from apartment area, in square meters: $\hat{y}=120+4.6x$. Two apartments differ by 30 square meters. How much do their predicted uses differ?

For bean plants, a line predicts growth, in centimeters, from fertilizer, in grams: $\hat{y}=5+0.42x$. If two plants differ by 20 grams of fertilizer, how much do their predicted growths differ?

A courier model predicts delivery time, in minutes, from distance, in kilometers: $\hat{y}=6+1.8x$. Two stops differ in distance by 12 kilometers. What is the predicted time difference?

A garden model predicts water use, in liters, from garden area, in square meters: $\hat{y}=18+2.5x$. Two gardens differ by 6 square meters. What is the predicted water-use difference?

A class model predicts quiz score, in points, from study time, in hours: $\hat{y}=50+6.0x$. Two students differ by 2.5 study hours. What is the predicted score difference?

A farm model predicts calf mass, in kilograms, from age, in months: $\hat{y}=35+18x$. If two calves differ in age by 3 months, how much do their predicted masses differ?

A calculator LinReg(a+bx) screen for 12 hardware stores predicts weekly paint sales, in liters, from floor area in hundreds of square meters. Predict sales for $x=30$.

For 10 school gardens, a calculator LinReg(a+bx) screen predicts bean yield, in kilograms, from compost, in kilograms. What is the slope?

A calculator LinReg(a+bx) screen is shown for 14 library programs and predicts attendance, in people, from advertising posters. Predict attendance when $x=12$ posters are used.

For 16 bike repairs, the calculator LinReg(a+bx) screen predicts cost, in dollars, from labor time, in hours. What is the y-intercept?

A calculator LinReg(a+bx) screen for 11 dairy farms predicts milk produced, in liters, from feed, in kilograms. Farms differing by 10 kg of feed differ by how much predicted milk?

Use the calculator LinReg(a+bx) screen for 13 delivery scooters that predicts maintenance cost, in dollars, from kilometers driven in hundreds. Predict cost when $x=8$.

The calculator LinReg(a+bx) screen for 15 clinics predicts daily waste, in kilograms, from patient count. What is the slope?

A calculator LinReg(a+bx) screen is given for 9 aquariums and predicts algae growth, in millimeters, from daily light, in hours. Predict growth for $x=9$ hours.