statistics
posted by Jessica .
A final exam in Math 157 is normally distributed and has a mean of 75 with a standard deviation of 12. If 36 students are randomly selected, find the probability that the mean of their test scores is greater than 70.

Z = (mean1  mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√(n1)(but you can use n)
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.
Respond to this Question
Similar Questions

statistics
Scores on a test are normally distributed with a mean of 68.2 and a standard deviation of 10.4. Estimate the probability that among 75 randomly selscted students, at least 20 of them score greater that 78. 
statistics
Scores on the ACT test are normally distributed with a mean of 21.1 and a standard deviation of 4.8. If one ACT score is randomly selected, find the probability that it is greater than 20. 
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 … 
Statistics
5. Scores on a recent national statistics exam were normally distributed with a mean of 80 and a standard deviation of 6. a. What is the probability that a randomly selected exam will have a score of at least 71? 
statistics
A final exam in sociology has a mean of 72 and a standard deviation of 9.2. If 35 students are randomly selected, find the probability that the mean of their test scores will be greater than 76. Round to tenth of a percent 
Statistics
Scores on a visual perception test are normally distributed with a mean of 2020 and a standard deviation of 250. a)If one subject is randomly selected and tested, find the probability of a score greater than 1800 b)if 50 subjects are … 
statistics
Scores on a visual perception test are normally distributed with a mean of 2020 and a standard deviation of 250. a)If one subject is randomly selected and tested, find the probability of a score greater than 1800 b)if 50 subjects are … 
statistics
Can you please tell me how to solve for the following? 
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 … 
math
Test scores on a university admissions test are normally distributed, with a mean of 500 and a standard deviation of 100. a. What is the probability that a randomly selected applicant scores between 425 and 575?