A competency test has scores with a mean of 69 and a standard deviation of 4. A histogram of the data shows that the distribution is normal. Use the Empirical Rule to find the percentage of scores between 61 and 77. Do not include the percentage sign with your response. For example 12% should be entered as 12.
Added by Teresa M.
Close
Step 1
Z-score for 61: (61 - 69) / 4 = -2 Z-score for 77: (77 - 69) / 4 = 2 Show more…
Show all steps
Your feedback will help us improve your experience
Thuc Nguyen and 65 other Intro Stats / AP Statistics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
A competency test has scores with a mean of 67 and a standard deviation of 6. A histogram of the data shows that the distribution is normal. Use the empirical rule to find the percentage of scores between 61 and 79. A. 95% B. 68% C. 99.7% D. 81.5%
Megha S.
A set of exam scores is normally distributed with a mean = 74 and standard deviation = 4. Use the Empirical Rule to complete the following sentences. 68% of the scores are between 70 and 78. 95% of the scores are between 66 and 82. 99.7% of the scores are between 62 and 86.
Tim T.
Assume a normal distribution. The mean score on a national aptitude test is 498 with a standard deviation of 100 points. (a) What percentage of the population has scores between 400 and $500 ?$ (b) If we sample 300 test-takers at random, about how many should have scores above $700 ?$
Applications of Definite Integrals
Applications from Science and Statistics
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD