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Grade 12 · Statistics

The normal distribution

207 problems in this skill, each with a solver-verified answer key. Answers are checked the moment you submit — with a hint if you want one and a worked solution afterwards.

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  1. Warm-up

    A data set is approximately normally distributed with mean μ=65\mu = 65 and standard deviation σ=12\sigma = 12. According to the empirical rule (the 68-95-99.7 rule), about what percent of the data lies in the interval μ±3σ\mu \pm 3\sigma?

  2. Warm-up

    A data set is approximately normally distributed with mean μ=58\mu = 58 and standard deviation σ=8\sigma = 8. According to the empirical rule (the 68-95-99.7 rule), about what percent of the data lies in the interval μ±3σ\mu \pm 3\sigma?

  3. Warm-up

    A data set is approximately normally distributed with mean μ=80\mu = 80 and standard deviation σ=13\sigma = 13. According to the empirical rule (the 68-95-99.7 rule), about what percent of the data lies in the interval μ±3σ\mu \pm 3\sigma?

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