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The number of cell phone minutes used by high school seniors follows a normal distribution with a mean of 500 and a standard deviation of 50. What is the probability that a student uses more than 350 minutes?

  • statistics -

    Use z-scores.

    Formula:

    z = (x - mean)/sd

    mean = 500
    sd = 50
    x = 350

    Substitute the values into the formula and find z. Use a z-table to determine your probability.

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