Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:

XX is a normally distributed random variable with mean 3434 and standard deviation 66. What is the probability that XX is between 1616 and 5252? Use the 0.680.950.9970.68-0.95-0.997 rule and write your answer as a decimal. Round to the nearest thousandth if necessary.

Full solution

Q. XX is a normally distributed random variable with mean 3434 and standard deviation 66. What is the probability that XX is between 1616 and 5252? Use the 0.680.950.9970.68-0.95-0.997 rule and write your answer as a decimal. Round to the nearest thousandth if necessary.
  1. Calculate Z-score for X=16X=16: Calculate the Z-score for X=16X = 16.Z=XμσZ = \frac{X - \mu}{\sigma}Z=16346Z = \frac{16 - 34}{6}Z=186Z = \frac{-18}{6}Z=3Z = -3
  2. Calculate Z-score for X=52X=52: Calculate the Z-score for X=52X = 52.Z=XμσZ = \frac{X - \mu}{\sigma}Z=52346Z = \frac{52 - 34}{6}Z=186Z = \frac{18}{6}Z=3Z = 3
  3. Use probability rule: Use the 0.680.68-0.950.95-0.9970.997 rule to find the probability.\newlineThe Z-scores 3-3 and 33 correspond to μ3σ\mu - 3\sigma and μ+3σ\mu + 3\sigma, respectively.\newlineAccording to the rule, the probability that XX is within 33 standard deviations of the mean (μ±3σ\mu \pm 3\sigma) is approximately 0.9970.997.
  4. Find probability between 1616 and 5252: The probability that XX is between 1616 and 5252 is approximately 0.9970.997.

More problems from Find probabilities using the normal distribution I