# statistics

posted by .

The population standard deviation (σ) for a standardized achievement test that is normally distributed is 8.
a.) Calculate the standard error of the mean if you draw a random sample of 50 test scores.  Show your work for full credit .  .  .
b.) Your sample mean is calculated to be 77.  Compute the 95% confidence interval for the mean.  Show your work!
c.) Interpret the meaning of the 95% confidence interval in one sentence.

• statistics -

Here are a few hints to get you started:

a). Standard error of the mean = standard deviation divided by the square root of the sample size

b). CI95 = mean ± 1.96(sd/√n)
...where ± 1.96 represents the 95% interval using a z-table, sd = standard deviation, and n = sample size

c). You are 95% confident that the population mean is within the interval.

## Similar Questions

1. ### statistics

Given a sample size of 38, with sample mean 660.3 and sample standard deviation 95.9 we are to perform the following hypothesis test. Null Hypothesis H0: ƒÊ = 700 Alternative Hypothesis H0: ƒÊ ‚ 700 At significance level 0.05 …
2. ### statistics

Suppose that the population standard deviation (ó) for a normally distributed standardized achievement test (ACT) is 6. What would the standard error of the sample mean (óxbar) be if we were to draw a random sample of 36 test scores?
3. ### statistics

the admissions policy at a certain university requires that incoming students score in the upper 20% on a standardized test. if the mean score on the test is 510 and the standard deviation of the scores is 80, what is the minimum score …
4. ### Statistics

Suppose. Population of test-scores is normally distributed with mean 65 and standard deviation 13 x~n (65,13) if you select a test at randome what is the probability that the score is below 60 or that it is between 65 and 70 please …
5. ### statistics

The scores for standardized test are normally distributed with a mean of 300 and standard deviation of 39. If the test is given to 700 students, how many are expected to have scores between 300 and 378.
6. ### 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 …
7. ### statistics

An IQ test was administered to a random sample of 26 mental patients and the mean was found to be 99.7. For this test, the population values are known to be normally distributed and with a population standard deviation of 15. Construct …
8. ### statistics

A large school district would like to estimate the mean score for all of its 5th grade students on a certain mathematics achievement test known to produce scores that are normally distributed in this population. In a pilot study, n …
9. ### Statistics

Scores on an SAT test have a mean of μ = 1026 and a standard deviation of σ = 209. Compute the margin of error of the sample mean for a random sample of 100 students.
10. ### statistics

10th grade New York public school students taking a standardized English test produced test scores that were normally distributed with a mean of 85 and a standard deviation of 4. Let x be a random variable that represents the test …

More Similar Questions