Math Problem Statement
A certain standardized test has scores which range from 0 to 500, with decimal scores possible. Scores on the exam are normally distributed with a mean of 308 and a standard deviation of 50.
What proportion of students taking the exam receive a score less than 366?
Round your answer to four (4) decimal places. (e.g. 0.1234)
Solution
To find the proportion of students who receive a score less than 366, we need to use the properties of the normal distribution.
Step 1: Standardize the score using the Z-score formula
The Z-score tells us how many standard deviations a score is away from the mean. The formula for the Z-score is:
Where:
- (the score we are interested in)
- (the mean score)
- (the standard deviation)
Substituting the values:
Step 2: Find the cumulative probability for Z = 1.16
Now, we need to look up the cumulative probability for in the standard normal distribution table or use a calculator that provides the cumulative probability.
For , the cumulative probability is approximately 0.8770.
Step 3: Conclusion
The proportion of students who score less than 366 is approximately 0.8770.
So, the answer is:
Let me know if you need further explanation or if you'd like to explore more! Here are some related questions:
- How would you find the proportion of students scoring above 366?
- What happens if the distribution is not normal?
- How can you use Z-scores to compare scores from different exams?
- What is the proportion of students scoring between 308 and 366?
- How would you find the score corresponding to a certain percentile?
Tip: If you ever need to find a percentile for a Z-score, simply look up the Z-score in the standard normal table or use a cumulative probability calculator.
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Math Problem Analysis
Mathematical Concepts
Statistics
Normal Distribution
Probability
Formulas
Z-score formula: Z = (X - μ) / σ
Cumulative probability from standard normal distribution table
Theorems
Empirical Rule
Properties of Normal Distribution
Suitable Grade Level
Grades 10-12, College Level Statistics
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