Assume that scores on a widely used standardized test are normally distributed with a mean of 750 and a standard deviation of 100. (Consider the distribution of scores to be a population.) If a university admits only the top 10% of the students taking the test, what is the lowest score a student can obtain and be admitted? What is the closest Z score corresponding to this value? What is the raw test score for this value?
We need to find the z1 such that:
P(z < z1) = 0.90
This means that all scores less than z1 have 90% of the students
From the z-table, z1 = +1.28
1.28 = (X - 750)/100
X = 750 + 128 = 878
X = 878 (z-score = 1.28) is the lowest score a student can obtain and be admitted.
Assume that scores on a widely used standardized test are normally distributed with a mean of...
1. The raw scores on the standardized reading test are normally distributed so the raw scores can be converted into a distribution of Z scores. If we want to mark the lower 5% of the distribution on the Z distribution, what is the Z value that is the cut-off point for that 5% tail region? (Answer with the exact Z value found from the Z table) 2. What would be the cut-off raw score if we want to mark the...
A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1474 and the standard deviation was 312. The test scores of four students selected at random are 1860,1230, 2170, and 1380. Find the z-scores that correspond to each value and determine whether any of the values are unusual. a)z-score for 1860 is b)z-score for 1230 is c)z-score for 2170 is d)z-score for 1380 is which values if any are unusual ?
A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1466 and the standard deviation was 310. The test scores of four students selected at random are 1860 1200 2160 and 1360. Find the z-scores that correspond to each value and determine whether any of the values are unusual.
A standardized exam's scores are normally distributed. In a recent year, the mean test score was 20.5 and the standard deviation was 5.4. The test scores of four students selected at random are 15, 23, 8, and 34. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 15 is The z- score for 23 is The z-score for 8 is The z-score for 34 is Which values, if any,...
The combined math and verbal scores for students taking a national standardized examination for college admission, is normally distributed with a mean of 660 and a standard deviation of 220. If a college requires a student to be in the top 20 % of students taking this test, what is the minimum score that such a student can obtain and still qualify for admission at the college?
A standardized visual working memory test has a population mean of 60 and a standard deviation of 6. Because the scores are normally distributed, the whole distribution of scores can be converted into a Z distribution. Each raw score in the original distribution has a corresponding Z score in the Z distribution. The Z distribution has a symmetrical bell shape with known properties, so it's possible to mathematically figure out the percentage of scores within any specified area in the...
A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1479 and the standard deviation was 316. The test scores of four students selected at random are 1880, 1220, 2180, and 1380. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1880 is Round to two decimal places as needed.) The z-score for 1220 is (Round to two decimal places as needed) The...
Proportions (percentages) in a Z Distribution A large population of scores from a standardized test are normally distributed with a population mean (μ) of 50 and a standard deviation (σ) of 5. Because the scores are normally distributed, the whole population can be converted into a Z distribution. Because the Z distribution has symmetrical bell shape with known properties, it’s possible to mathematically figure out the percentage of scores within any specified area in the distribution. The Z table provides...
Problem 3: Scores on an exam are assumed to be normally distributed with mean /u = 75 and variance a2 = 25 (1) What is the probability that a person taking the examination scores higher than 70? (2) Suppose that students scoring in the top 10.03% of this distribution are to receive an A grade. What is the minimum score a student must achieve to earn an A grade? (3) What must be the cutoff point for passing the examination...
Scores on a test of reading ability for second graders are normally distributed with a mean of 60 and a standard deviation of 11. The principal of a school wants to identify the students who are in the top 5% of the class for participation in accelerated work in reading. What is the minimum raw score a student must have to be in the top 5% a. 65 b. 78.5 c. 66.65 d. 77.58