Suppose that the distribution of marks on an exam is closely described by a normal curve...
Suppose that the distribution of marks on an exam is closely described by a normal curve with a mean of 65. The 84th percentile of this distribution is 75. (a) What is the 16th percentile? (b) What is the approximate value of the standard deviation of exam marks? (c) What z-score is associated with an exam mark of 50? (d) What percentile corresponds to an exam mark of 85? (e) Do you think there were many marks below 35? Explain.
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Suppose that the distribution of marks on an exam is closely
described by a normal curve...
Suppose that the distribution of marks on an exam is closely described by a normal curve...
Suppose that the distribution of marks on an exam is closely described by a normal curve with a mean of 65. The 84th percentile of this distribution is 75. (a) What is the 16th percentile? (b) What is the approximate value of the standard deviation of exam marks? (c) What z-score is associated with an exam mark of 50? (d) What percentile corresponds to an exam mark of 85? (e) Do you think there were many marks below 35? Explain.
Consider a normal distribution curve where 85-th percentile is at 15 and the 35-th percentile is...
Consider a normal distribution curve where 85-th percentile is at 15 and the 35-th percentile is at 7. Use this information to find the mean, μ , and the standard deviation, σ , of the distribution.
18. Suppose the random variable x is best described by a normal distribution with u =...
18. Suppose the random variable x is best described by a normal distribution with u = 30 and o = 7.9. Find the Z-score that corresponds to each of the following x values. a. X=36, z= b. X=35, z=_ c. X=22, ze d. X=30, ZE e. X=19, ZF f. X=36, z
scores on an exam required for all medical school applicants were approximately normal with a mean...
scores on an exam required for all medical school applicants were approximately normal with a mean of 420 and a standard deviation of 8.2. a.) suppose an applicant had a test score of 520. what percentile corresponds with this score? b.) suppose to be considered at a highly selective school and applicant need to score the top 10%. what score would place the applicant on top of 10%
Suppose a random variable x is best described by a normal distribution with = 60 and...
Suppose a random variable x is best described by a normal distribution with = 60 and sigma=16. Find the z-score that corresponds to the value x = 0. 0 -3.75 0-16 O 16 0 3.75
For statistics expert The data in the table are simulated exam scores. Suppose the exam was...
For statistics expert
The data in the table are simulated exam scores. Suppose the exam was given in the semester after the course content was revised, and the previous mean exam score was 70. We would like to know whether or not the mean score has increased. Answer the following question using any approximate method by stating the necessary assumptions. The data are here: Simulated Exam Scores 75 70 88 80 80 66 65 68 85 80 78 72 69...
Suppose that, for a certain exam, a teacher grades on a curve. It is known that...
Suppose that, for a certain exam, a teacher grades on a curve. It is known that the mean is 65 and the standard deviation is 10. There are 30 students in the class. What score would be necessary to obtain an A?
1. (5 points) Suppose Z is a random variable that follows the standard normal distribution. a)...
1. (5 points) Suppose Z is a random variable that follows the standard normal distribution. a) Find P(Z > 0.45). b) Find P(0.7 SZ 1.6). c) Find 20.09. d) Find the Z-score for having area 0.18 to its left under the standard normal curve. e) Find the value of z such that P(-2SZS2) -0.5. 3. (4 points) The scores on a test are normally distributed with a mean of 75 and a standard deviation of 8. a) Find the proportion...
Auto insurance premiums. Suppose a newspaper article states that the distribution of auto insurance premiums for...
Auto insurance premiums. Suppose a newspaper article states that the distribution of auto insurance premiums for residents of California is approximately normal with a mean of 1598. The article also states that 10% of California residents pay more than 1850. 1. What is the Z score that corresponds to the top 10% (or the 90thth percentile) of the standard normal distribution? Round your answer to 4 decimal places. 2. What is the mean insurance cost? 3. What is the cutoff...
Auto insurance premiums. Suppose a newspaper article states that the distribution of auto insurance premiums for...
Auto insurance premiums. Suppose a newspaper article states that the distribution of auto insurance premiums for residents of California is approximately normal with a mean of 1619. The article also states that 25% of California residents pay more than 1940. 1. What is the Z score that corresponds to the top 25% (or the 75thth percentile) of the standard normal distribution? Round your answer to 4 decimal places. 2. What is the mean insurance cost? 3. What is the cutoff...
18. Suppose the random variable x is best described by a normal distribution with u = 30 and o = 7.9. Find the Z-score that corresponds to each of the following x values. a. X=36, z= b. X=35, z=_ c. X=22, ze d. X=30, ZE e. X=19, ZF f. X=36, z
Suppose a random variable x is best described by a normal distribution with = 60 and sigma=16. Find the z-score that corresponds to the value x = 0. 0 -3.75 0-16 O 16 0 3.75
For statistics expert
The data in the table are simulated exam scores. Suppose the exam was given in the semester after the course content was revised, and the previous mean exam score was 70. We would like to know whether or not the mean score has increased. Answer the following question using any approximate method by stating the necessary assumptions. The data are here: Simulated Exam Scores 75 70 88 80 80 66 65 68 85 80 78 72 69...
1. (5 points) Suppose Z is a random variable that follows the standard normal distribution. a) Find P(Z > 0.45). b) Find P(0.7 SZ 1.6). c) Find 20.09. d) Find the Z-score for having area 0.18 to its left under the standard normal curve. e) Find the value of z such that P(-2SZS2) -0.5. 3. (4 points) The scores on a test are normally distributed with a mean of 75 and a standard deviation of 8. a) Find the proportion...
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