Question

an independent third party found the cost of a basic car repair service for a local magazine. the mean cost is $217.00 with a standard deviation of $11.40. which of the following repair costs would be considered an “unusual” cost? (1 point) $233.87 $197.24 $221.65 $192.53

Explanation:

Step1: Determine the range for usual values

Usual values are within \( \mu\pm2\sigma\) (where \(\mu\) is the mean and \(\sigma\) is the standard deviation).
\(\mu = 217\), \(\sigma=11.4\)
Lower limit: \(217 - 2\times11.4=217 - 22.8 = 194.2\)
Upper limit: \(217+ 2\times11.4=217 + 22.8=239.8\)

Step2: Check each value

• For \(233.87\): \(194.2<233.87<239.8\) (usual)
• For \(197.24\): \(194.2<197.24<239.8\) (usual)
• For \(221.65\): \(194.2<221.65<239.8\) (usual)
• For \(192.53\): \(192.53<194.2\) (unusual)

Answer:

\(\$192.53\)