Precision v. Accuracy
Define precision and accuracy and give a real‑world example (differentiate the two).
Precision - How close measurements are to one another
Accuracy - How close a measurement is to the actual value
Describe what a composite shape is.
Give an example
What is a figure made up of multiple shapes?
Johnnie got 3 problems out of 5 correct; calculate his score.
What is 60%?
If an item costs $45.00 and the sales tax rate is 7%, what is the total cost? Round to the nearest cent.
What is $48.15?
A diner wants to leave a 15% tip on a $24.00 meal. How much is the tip? Round to the nearest cent.
What is $3.60?
A lab instrument reports repeated measurements of a length as 5.02 cm, 5.01 cm, 5.03 cm. The true length is 5.50 cm. Why?
What is Precision?
A rectangle measures 8 m by 4 m. A semicircle of radius 2 m sits on one short side. Find the total area (use 𝝅 = 3.1416). Round to the nearest hundredth.
What is 38.28 m2?
18% of $250: Round to the nearest cent.
What is $45.00?
A purchase totals $128.75 before tax. If combined state and local tax is 8.25%, compute the final price. Round to the nearest cent.
What is $139.40?
Calculate a 20% tip on a bill of $48.35. Round to the nearest cent.
What is $9.67?
A student obtains measurements 12.4 cm, 12.6 cm, 12.5 cm for a side of a square. Calculate the area using the average measurement. If the actual area is 132.45 square cm; describe these measurements.
What is precise but not accurate?
A composite figure consists of a right triangle with base 6 cm and height 4 cm attached to a rectangle of width 6 cm and height 3 cm. Some region of the composite figure is shaded: the triangle and half the rectangle. Find the percent of the whole figure that is shaded. Round to the nearest tenth of a percent.
What is 70.0%?
A student earned 42 out of 50 points on an assignment. What percent did they earn? Round to the nearest tenth of a percent.
What is 84%?
A city increases its sales tax from 6% to 6.75%. For a $2,000 purchase, how much more tax will the buyer pay because of the increase? Round to the nearest cent.
What is $15.00?
A group of four splits a bill of $92.40 before tip. They agree to leave an 18% tip. How much does each person pay including an even split of the tip? Round to the nearest cent.
What is $27.26?
An experimental device consistently measures a mass 2.5% lower than the accepted mass. If the accepted mass is 1000 g, the reading the device reports____.
Explain whether this is a precision or accuracy issue and propose one method to improve accuracy. (Round to the nearest tenth.)
What is 975 g?
A square of side 10 cm has a circle of radius 3 cm removed from its center. Find the percent of the square that is shaded (the shaded area is the square minus the circle). Round to the nearest hundredth of a percent.
What is 71.73%?
A scientist reports that a sample contains 0.045 of a pollutant by mass. Express this as a percent and round to the nearest tenth of a percent.
What is 4.5%?
A bundled purchase shows a pre‑tax price of $987.60. If tax is 9.125%, compute the total tax amount and round to the nearest cent.
What's the total cost?
What is $90.12?
Total: $1,077.72
A waiter received a 12% tip on a bill, which amounted to $10.80. What was the pre‑tip bill? Round to the nearest cent.
What is $90.00?
A set of five measurements for a value: 9.872, 9.875, 9.870, 9.873, 9.871. Compute the average.
Based on results, evaluate precision and state whether the mean is likely accurate if the true value is 9.900. Round mean to the nearest thousandth.
What is 9.872?
What is precise but not accurate?
A composite playground surface is made of a large semicircle of radius 20 ft attached to a rectangle 40 ft long and 10 ft wide (the semicircle sits on the width). A triangular sandbox of base 10 ft and height 8 ft is inside the rectangle and is shaded. Find the percent of the entire composite area that the sandbox occupies. Round to the nearest tenth of a percent.
What is 2.4%?
A county’s population grew from 120,000 to 134,400 over one year. Calculate the percent increase. Show the value rounded to the nearest hundredth of a percent.
What is 10.71%?
A state applies different tax rates: essentials at 2.5% and luxury goods at 9%. A shopper buys $350 of essentials and $1,250 of luxury goods. Compute the combined tax and the final total paid. Round to the nearest cent.
What is $121.25?
Total: $1,721.25
After taxes, a restaurant bill is $156.78. The party decides to tip 18% of the pre‑tax amount. If the tax rate was 7.5%, compute the total amount paid including tax and tip. Round all monetary values to the nearest cent.
What is $182.88?