Question

In: Statistics and Probability

An instructor gives a 100-point test in which the grades are approximately normally distributed. The mean...

An instructor gives a 100-point test in which the grades are approximately normally distributed. The mean is 65 points and the standard deviation is 12 points.

a. What is the lowest possible score to qualify in the top 5% of the scores?

b. If 500 students took the test, how many students received a score between 60 and 80 points?

( I hope the solution to the questions can be provided as well )

Solutions

Expert Solution


Related Solutions

An instructor gives a 100 point exam which grades are normal distributed. the mean is 66...
An instructor gives a 100 point exam which grades are normal distributed. the mean is 66 and the standard deviation is 8. If there are 12% A, 10% B, 60% C, 10% D, and %8 F. find the scores and then divide the distribution into those categories. Suppose 50 students were selected from a class who took the exam in the above problem. What is the probability the class average was a 65 and a 67?
Score on a 100-point test is normally distributed with mean 87.7.   You took a sample of...
Score on a 100-point test is normally distributed with mean 87.7.   You took a sample of 36 students. The mean for this group is 92 and the standard deviation is 15.               Test the hypothesis that the performance of this group is different than the regular student population. Use α=.05. What is the alternative hypothesis? What is the value of the test statistic? would you use the t test? What is the rejection region? the decision is to not reject the...
The grades on a statistics test are normally distributed with a mean of 62 and Q1=52....
The grades on a statistics test are normally distributed with a mean of 62 and Q1=52. If the instructor wishes to assign B's or higher to the top 30% of the students in the class, what grade is required to get a B or higher? Please round your answer to two decimal places. The distribution of scores on a recent test closely followed a Normal Distribution with a mean of 22 points and a standard deviation of 2 points. For...
Scores of a standardized test are approximately normally distributed with a mean of 85 and a...
Scores of a standardized test are approximately normally distributed with a mean of 85 and a standard deviation of 5.5. (a) What proportion of the scores is above 90? (b) What is the 25th percentile of the scores? (c) If a score is 94, what percentile is it on?
Score (X) on a 100-point test is normally distributed with mean 89 and standard deviation 10.                           
Score (X) on a 100-point test is normally distributed with mean 89 and standard deviation 10.                                                          What is the following probability: P(85 < X < 95) You took a sample of 25 students from the population in I. What is the following probability:                P(85 < Xbar < 95)
Suppose IQ scores are approximately normally distributed with a mean of 100 and a standard deviation...
Suppose IQ scores are approximately normally distributed with a mean of 100 and a standard deviation of 15. Answer the following questions. Question 1 What percent of the population has an IQ that is above average? Question 2 What percent of the population has an IQ below 110? What is the calculated z-score? What is the percentage? Question 3 What percent of the individuals in the population have an IQ above 130? (Individuals in this category are sometimes classified as...
Suppose IQ scores are approximately normally distributed with a mean of 100 and a standard deviation...
Suppose IQ scores are approximately normally distributed with a mean of 100 and a standard deviation of 15. Answer the following questions. Question 1 What percent of the population has an IQ that is above average? Question 2 What percent of the population has an IQ below 110? What is the calculated z-score? What is the percentage? Question 3 What percent of the individuals in the population have an IQ above 130? (Individuals in this category are sometimes classified as...
2. The IQ of humans is approximately normally distributed with a mean 100 and standard deviation...
2. The IQ of humans is approximately normally distributed with a mean 100 and standard deviation of 15. A. What is the probablitlty that a randomly selected person has an IQ greater than 105? B. What is the probablitlty that a SPS of 60 randomly selected people will have a mean IQ greater than 105? 3. A 95% confidence interval for a population mean is (57,65). Can you reject the null hypothesis the mean= 68 at the 5% significance level...
2. The IQ of humans is approximately normally distributed with a mean 100 and standard deviation...
2. The IQ of humans is approximately normally distributed with a mean 100 and standard deviation of 15. A. What is the probablitlty that a randomly selected person has an IQ greater than 105? B. What is the probablitlty that a SPS of 60 randomly selected people will have a mean IQ greater than 105? 3. A 95% confidence interval for a population mean is (57,65). Can you reject the null hypothesis the mean= 68 at the 5% significance level...
There is a test which is normally distributed with a mean of 30 and a standard...
There is a test which is normally distributed with a mean of 30 and a standard deviation of 4. Find the probability that a sample of 36 scores will have a mean at most 31.5.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT