Question

In a certain sporting goods manufacturing company, a quality control expert tests a randomly selected group of $1,000$ tennis balls in order to determine how many contain defects. If this quality control expert discovered that $13$ of the randomly selected tennis balls were defective, select the most appropriate inference from the following.

• A. $98.7\%$ of the company's tennis balls are defective
• B. $98.7\%$ of the company's tennis balls are not defective
• C. $9.87\%$ of the comany's tennis balls are defective
• D. $9.87\%$ of the company's tennis balls are not defective

Answer 1

The correct option is B $98.7\%$ of the company's tennis balls are not defective

Given that quality control expert test $1000$ tennis balls in order .

In this order quality control expert discovered that $13$ balls are defective.

Then better balls are $=1000-13=987$

Then $\%$ of not defective tennis balls $=$ $\frac{987}{1000}\times 100=98.7$

So (B) is write answer that $98.7\%$ of the company tennis balls are not defective