statistics

A used car dealership has found that the length of time before a major repair is required on the cars it sells is normally distributed with a mean of 10 months and a standard deviation of 3 months. If the dealer wants only 5 percent of the cars to fail before the end of the guarantee period for how many months should the cars be guaranteed?

asked by victoria
  1. You will need to find the z-score using a z-table. Remember the question is asking that the dealer wants only 5% of the cars to fail. Keep that in mind when looking for the z-score.

    z = (x - mean)/sd -->z-score formula

    Substitute the z-score you found, the mean, and the standard deviation into the formula, then solve for x.

    I'll let you take it from there.

    posted by MathGuru
  2. 23

    posted by K

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