# Probability and Statistics

posted by .

The ACT scores of applicants to college are approximately normally distributed with a mean of 20.3 and a standard deviation of 3.1. If a random sample of 20 applicants to college is chosen find the probability that their average ACT score will be 19 and 21.

• Probability and Statistics -

68%!

• Probability and Statistics -

Here is the method.

Z = (score-mean)/SEm

SEm = SD/√n

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

## Similar Questions

1. ### math

Suppose that a college admissions office needs to compare scores of students who take the Scholastic Aptitude test(SAT) wit those who take the american college test (ACT). Suppose that among the college's applicants who take the SAT, …
2. ### stats help!

thank you in advance! in a given year the college admissions office accepts applicants from students, who are then either accepted or not accepted. accepted students may or may not decide to attend college. suppose the scores on a …
3. ### statistics

A bank’s loan officer rates applicants for credit. The ratings are normally distributed with a mean of 175 and a standard deviation of 15. If an applicant is randomly selected, find the probability of a rating that is between 150 …
4. ### statistics

Pleas HeLp!!!!!!!!!! A random sample of the test scores of 100 applicants for college entry at a large junior college showed a mean score of 72.6. Determine a 99%, 95%, and 90% confidence interval for the m mean score of all applicants …
5. ### statistics

Suppose a random sample of 25 students is selected from a community college where the scores in the final exam (out of 125 points) are normally distributed, with mean equal to 112 and standard deviation equal to 12. Find the probability …
6. ### statistic

Suppose a random sample of 25 students is selected from a community college where the scores in the final exam (out of 125 points) are normally distributed, with mean equal to 112 and standard deviation equal to 12. Find the probability …
7. ### statistics

Scores on the ACT college entrance exam are Normally distributed with a mean µ = 20 and standard deviation σ = 5. An SRS of 25 ACT scores is selected, construct a 95% Confidence Interval for the sample mean (X-Bar) and interpret …
8. ### statistics

Suppose that the test scores for a college entrance exam are normally distributed with a mean of 450 and a standard deviation of 100. If a student is selected at random what is the probability that the student will score above 600?
9. ### statistics

Scores on a national writing exam are approximately normally distributed, with a mean of 490 and a standard deviation of 20. Consider random samples of size 25 from the population of test takers. describe the sampling distribution …
10. ### probability

The National Center for Educational Statistics reported that in 2009 the ACT college placement and admission examination were normally distributed and had a mean of 21.1 and standard deviation of 5.1. A college requires applicants …

More Similar Questions