Math Problem Statement

A distribution of values is normal with a mean of 33.5 and a standard deviation of 75.5.

Find the probability that a randomly selected value is between 184.5 and 237.4. P(184.5 < X < 237.4) = 0.0208 Incorrect

Enter your answer as a number accurate to 4 decimal places. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

Solution

To solve P(184.5<X<237.4)P(184.5 < X < 237.4), we need to standardize the values using the Z-score formula:

Z=XμσZ = \frac{X - \mu}{\sigma}

Where:

  • μ=33.5\mu = 33.5 (mean)
  • σ=75.5\sigma = 75.5 (standard deviation)
  • XX is the value we're calculating the Z-score for.

Step 1: Compute Z-scores

For X=184.5X = 184.5:

Z1=184.533.575.5=151.075.52.000Z_1 = \frac{184.5 - 33.5}{75.5} = \frac{151.0}{75.5} \approx 2.000

For X=237.4X = 237.4:

Z2=237.433.575.5=203.975.52.701Z_2 = \frac{237.4 - 33.5}{75.5} = \frac{203.9}{75.5} \approx 2.701

Step 2: Find the probabilities using the standard normal distribution

Using a Z-table or a calculator:

  • P(Z1=2.000)0.9772P(Z_1 = 2.000) \approx 0.9772
  • P(Z2=2.701)0.9964P(Z_2 = 2.701) \approx 0.9964

Step 3: Calculate the probability

The probability that XX is between 184.5 and 237.4 is:

P(184.5<X<237.4)=P(Z2)P(Z1)P(184.5 < X < 237.4) = P(Z_2) - P(Z_1)

P(184.5<X<237.4)=0.99640.9772=0.0192P(184.5 < X < 237.4) = 0.9964 - 0.9772 = 0.0192

Final Answer:

P(184.5<X<237.4)=0.0192P(184.5 < X < 237.4) = 0.0192

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Math Problem Analysis

Mathematical Concepts

Probability
Normal Distribution
Z-Scores

Formulas

Z = (X - μ) / σ
P(a < X < b) = P(Zb) - P(Za)

Theorems

Properties of the Standard Normal Distribution

Suitable Grade Level

Grades 10-12