# Statistics

posted by .

The next three questions refer to the following situation. Data from previous years reveal that the distribution if first exam scores in an introductory statistics class is approximately normal with a mean of 72 and a standard deviation of 12.

16) Given that the passing score is 65, approximately what percentage of students passes the first exam?

17) What is the probability that the student will score an “A” on the exam? (A score of 90 or more)

18) The middle 95% of the scores will tend to fall between _________ and ________.

• Statistics -

16. Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to to the Z score.

17. Use same equation and table.

18. Use table to find P = ± ,45 to get the two Z scores. Insert into equation above.

## Similar Questions

1. ### Statistics

Students were given an exam with 300 multiple-choice questions. The distribution of the scores was normal and mean was 195 with a standard deviation of 30. What were the scores of the students who were within one standard deviation …
2. ### statistics

Answer the question(s) based on the following situation: 150 students in a math class take the final exam. The scores on the exam have an approximately normal distribution with center ì = 65 and standard deviation ó = 10.The third …
3. ### Analytical Skills

If your score on a statistics exam was 76 and the professor gave you the distribution for the exam score for your class, you could find your percentile to understand where you stand in comparison to your fellow students. Assume that …
4. ### math

Statistics: Analyze student exam scores Students were given an exam with 300 multiple choice questions. The distribution of the scores were normal and the mean was 195 with a standard deviation of 30. you may find it helpful to draw …
5. ### statistics

Scores from a statistics exam are reported as deviation scores. Which of the following deviation scores indicates a higher position in the class distribution?
6. ### stats

Relatively speaking, which statistics exam did you do better on?
7. ### Math/Statistics

A statistics teacher believes that the final exam grade for her elementary stats class have a normal distribution with a mean of 82 and a standard deviation on 8. Find the score which separates the top 10% of the scores from the lowest …
8. ### statistics

Scores on a national exam assume a normal distribution with a population mean of 50 and population standard deviation of 10 points. A sample of 36 exam scores was selected from UCA with a mean score of 58 points. Using a significance …
9. ### Statistics

One hundred students took a statistics exam where the mean score was 78. The distribution was normal. The standard deviation was 4. If Chris earned an 80 on the exam, at approximately what percentile did his grade fall?
10. ### College statistics- SCWK450

One hundred students took a statistics exam where the mean score was 78. The distribution was normal. The standard deviation was 4. If Chris earned an 80 on the exam, at approximately what percentile did his grade fall?

More Similar Questions