
27 The scores on a test are romany direbuted with a mean of 60 and a...
a.) Test scores are normally distributed with a mean of 60 and a variance of 225. Joe scored at the 90th percentile which means that his score was? b.) Suppose X is normally distributed with mean 4 and standard deviation 4. Find the probability that 2X exceeds 7. c.) Test scores are normally distributed with a mean of 60 and a standard deviation of 15. Joe scored at the 95th percentile which means that his score was d.) a random...
The scores on a state's ACT test in a recent year averaged out to 22.3 with a standard deviation of 6.2. A-how likely is it that a single student test-taker randomly chosen in the state earned a score of 27? B-How likely is it that a student scored 27 or higher? C- A simple random sample of 16 students took the test. What are the mean and standard deviation of the sampling distribution of these 16 scores? D- What is...
27. On a standardized test with a normal distribution, the mean was 64.3 and the standard deviation was 5.4. What is the best approximation of the percent of scores that fell between 61.6 and 75.1? 28. The mean of a normally distributed set of data is 52 and the standard deviation is 4. Approximately 95% of all the cases will lie between which measures? 29. Battery lifetime is normally distributed for large samples. The mean lifetime is 500 days and...
A test of reading ability has mean 60 and standard deviation 5 when given to third graders. Sixth graders have mean score 83 and standard deviation 11 on the same test. To provide separate "norms" for each grade, we want scores in each grade to have mean 100 and standard deviation 20. (Round your answers to two decimal places.) (a) What linear transformation will change third-grade scores x into new scores xnew = a + bx that have the desired...
The scores on a lab test are normally distributed with mean of 200. If the standard deviation is 20, find: a) The score that is 2 standard deviations below the mean b) The percentage of scores that fall between 180 and 240 c) The percentage of scores above 240 d) The percentage of scores between 200 and 260 e) The percentage of scores below 140
The equation B= 60 x A + 120 can be used to convert scores on standardized test A to scores on standardized test B. Treat A and B in this equation as random variables. a) Suppose a school has a mean score on test A of 25 . What is its equivalent mean score on test B? b) If one school has a standard deviation of 4 points on test A, what is the standard deviation of its equivalent score...
Scores by women on the SAT-1 test are normally distributed with a mean of 988 and a standard deviation of 202. Scores by women on the ACT test are normally distributed with a mean of 20.9 and a standard deviation of 4.6. If a women gets a SAT score that is the 77th percentile, find her actual SAT score and her equivalent ACT score.
in a certain class, test scores average out to 60, with a standard deviation of 20, as do scores on the final. The correlation between test scores and the final scores is about 0.5. Estimate the average final score for the students whose test score was: 60 A. 60 B. 70 C. 50 D. 80
Solve the problem. Scores on a test are normally distributed with a mean of 78 and a standard deviation of 14. What is the standard score ( 2 score) for an exam score of 66 ? -0.86 -0.67 0.67
the scores on a certain test are normally distributed with a mean score of 65 and a standard deviation of 2. what is the probability that a sample of 90 students will have a mean score of at least 65.2108.