Math 3202

 Accuracy is the degree to which a measurment is measured and reported correctly  Precision is the degree of exactness to which a measurement is expressed. It depends on the scale of the instrument used.

 This angle could be read as 46.5, 47, or even 48. These are all accurate measurements, but they vary in precision.

 NOTE: Be careful about units!!!  One very common measuring error is to measure something properly but state the measurement in the wrong units.  For example a door is about 60 inches wide, if you said it was 60 feet wide you would be way off!!!!

 Explore Accuracy and Precision on page 7 of the text.

 Vic and his son are going to pour a concrete pad before building a shed. They want the pad to be 12 ft long, 8 ft wide, and 4 in thick.  Vic’s son wants to calcuate the volume of the concerete needed. He knowns that: Volume = Length x Width x Height (or thickness).  So he thinks: V = lwh V = 12 x 8 x 4 V = 392.

 Vic’s Son says: “We need 392 cubic feet of concrete”  Vic says, “No way, we only neeed 32 cubic feet”

Question a) Whose calculation is accurate? Explain b) Is it important for this calculation to be accurate? Explain.

Your Turn: Calculate the volume of concrete needed for a pad that measures 20 ft by 10 ft by 6 in.

 Check Your Understanding on page 9 & 10

 Greg is redecorating a bedroom in his house. He knows that his measurements need to be accurate, but the degree of precision required depends on the job.

 Your Turn  A) A second bedroom in Greg’s house has dimensions that are 10 ‘ 4 “ by 13 ‘ 10 “. The ceiling is 7’ 10½ “ high. He wants to paint the bedroom, how much paint should he buy?  B) A closet door in the bedroom is 80” high and 24” wide. Determine the length he should cut the horizontal piece of casing that goes across the top of the closet door frame.

 Check Your Understanding on page

 A clothing manufacturer seems men’s pants. Men’s pants are measured in whole-inch sizes by their waist measurement and, often, by their inseam measurement as well. The company allows for a tolerance of ± ¼ “ when labelling their products.

 A) What is the tolerance in the waits measurement of a pair of pants?  B) What are the maximum and minimum allowable waist and measurements that can be labeled as 32 inch waist pants?

 A) What is the tolerance for the neck measurement of a men’s shirt?  B) What are the maximum and minimum allowable measurements that can be sold as a men’s shirt with a 15” neck?

 Check Your Understanding on page 16-17

 Work With It: Page 18-19