Question

In: Statistics and Probability

Descriptive analysis revealed that the mean Test 3 score of all 63 students in Dr. Bills’s...

Descriptive analysis revealed that the mean Test 3 score of all 63 students in Dr. Bills’s statistics courses was an 80. Similarly, the standard deviation for all students’ Test 3 scores was found to be 16. Assume the Test 3 scores are approximately normally distributed.

5. Determine the Test 3 score that corresponds to a z-score of -2.18. Round your solution to the nearest whole number.

6. Find the 75^th percentile. That is, find the test score such that 75% of all test scores are below it. Hint: See example on the Chapter 6 handout. Round your solution to the nearest whole number.

Solutions

Expert Solution

Mean = = 80

standard deviation = = 16

Sample size = n = 63

5. Determine the Test 3 score that corresponds to a z-score of -2.18. Round your solution to the nearest whole number.

z = -2.18

6. Find the 75^th percentile. That is, find the test score such that 75% of all test scores are below it.

We need to find such that

We know that

orchestra answered 11 months ago

Next > < Previous

Related Solutions

Descriptive analysis revealed that 68% of students passed Test 1. Suppose a random sample of 18...

Descriptive analysis revealed that 68% of students passed Test 1. Suppose a random sample of 18 students is selected and defined ˆp as the proportion of students in the sample who passed Test 1. Determine the mean of the sampling distribution of ˆp. μˆp= Determine the standard deviation of the sampling distribution of ˆp. Round the solution to six decimal places. σˆp= Determine the probability that between 63.3% and 77.3% of a random sample of 18 students passed Test 3....

Suppose it is desired to test the hypothesis that the mean score of students on a...

Suppose it is desired to test the hypothesis that the mean score of students on a national examination is 500 against the alternative hypothesis that it is less than 500. A random sample of 15 students is taken from the population and produces a sample mean score of 475 and a sample standard deviation of 35. Assume the population of test scores is normally distributed. State the decision rule, the test statistic, and your decision.

Suppose it is desired to test the hypothesis that the mean score of students on a...

I asked 100 students to complete a statistics test. the mean score on the test was...

I asked 100 students to complete a statistics test. the mean score on the test was 30 points with a standard deviation of 5 points. using this information and the normal distribution, calculate the following: [want to check my overall answers and help with the process of some] thank you a. what is the probability a student earned a score of 45 points or less? P(score <45 points) i got 0.9987 b. what is the probability a student earned a...

In a psychology class, 59 students have a mean score of 98 on a test. Then...

In a psychology class, 59 students have a mean score of 98 on a test. Then 16 more students take the test and their mean score is 62.8. What is the mean score of all of these students together? Round to one decimal place. mean of the scores of all the students = 57 randomly selected students were asked how many siblings were in their family. Let X represent the number of pairs of siblings in the student's family. The...

A research is interested in whether the mean score on a particular aptitude test for students...

A research is interested in whether the mean score on a particular aptitude test for students who attend rural elementary schools is higher than the score of elementary school students in general (ux=50), ox=10). She tests a random sample of 28 rural elementary school students and finds the sample mean to be 56. Using alpha=.05, conduct the 8 steps hypothesis testing to determine whether the rural elementary school students have a significantly higher aptitude score than elementary students in general.

Statistics students believe that the mean score on a first statistics test is 65. The instructor...

Statistics students believe that the mean score on a first statistics test is 65. The instructor thinks that the mean score is higher. She samples 10 statistics students and obtains the scores: Grades 73.5 68.4 65 65 63.9 68.4 64.3 66.5 61.9 69 Test grades are believed to be normally distributed. Use a significance level of 5%. State the standard error of the sample means: (Round to four decimal places.) State the test statistic: t=t= (Round to four decimal places.) State the...

The scores of all females’ math test writing in June 2012 had a mean of 63...

The scores of all females’ math test writing in June 2012 had a mean of 63 (in percent). Assume that these scores can be modeled by the Normal distribution with a standard deviation of 10 (in percent). a) A girl is randomly selected from all females whose scores are higher than 75%. What is the probability that this girl has a score higher than 96%? b) One thousand people are randomly selected. Approximately what is the probability that fewer than...

3. The national mean score of an aptitude test is 50 with a standard deviation of...

3. The national mean score of an aptitude test is 50 with a standard deviation of 5. I think students at Ohio University can earn higher scores than people nationally. I survey 30 students at Ohio University and find a mean 57 with a standard deviation of 6.8. Is the mean scores of Ohio University students significantly more than the mean score of the aptitude test nationally? (use  = .05) a. State the null and alternative hypotheses in symbols....

1.I recently asked 100 middle school students to complete a statistics test. The mean score on...

1.I recently asked 100 middle school students to complete a statistics test. The mean score on the test was 30 points with a standard deviation of 5 points. The scores followed a normal distributions. Using this information, calculate the following: a. What is the probability a student earned a score of 45 points or less? P (score < 45 points) = b. What is the probability a student earned a score higher than 30 points? P(score > 30) = c....

Subjects