Multiple choice

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.

  1. $98.7\%$ of the company's tennis balls are defective
  2. $98.7\%$ of the company's tennis balls are not defective
  3. $9.87\%$ of the comany's tennis balls are defective
  4. $9.87\%$ of the company's tennis balls are not defective
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sample size is 1,000, and 13 were defective. The defect rate is 13/1000 = 0.013 or 1.3%. The non-defect rate is 1 - 0.013 = 0.987, which is 98.7%.

AI explanation

Out of the 1000 randomly selected tennis balls, 13 were found to be defective. The number of non-defective tennis balls in this sample is 1000 minus 13, which equals 987. Therefore, the inference is that 98.7 percent of the company's tennis balls are not defective.

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