Statistics

posted by .

find the 90% confidence interval for the variance and standard deviation of the ages of seniors at Oak Park College if a sample of 24 students has a standard deviation of 2.3 years. Assume the variable is normally distributed. Can someone explain the steps to solve this? Thanks so much.

• Statistics -

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the Z score for .4500 from mean (Z = 1.645)

90% conf. Interval = mean ± 1.645(SD)

• Statistics -

A party host gives a door prize to one guest chosen at random. There are 48 men and 42 women at the party. What is the probability that the prize goes to a woman? Round your answer to 3 decimal places.

• Statistics -

That is incorrect. You do not use the Z-score for the mean. This is a Chi-square distribution.
1-.9=.10/2 (for left and right alpha tail) = .05
Find .05 and .95 using the d.f.=23
That equals 34.172 and 13.091
Using the formula for the variance which is ((n-1)s^(2))/(x^(2))
3.46<variance<9.29

Similar Questions

1. Statistics

find the 90% confidence interval for the variance and standard deviation of a sample of 16 and a standard deviation of 2.1 Assume the variable is normally distributed.
2. elizabeth high school

. An admissions director wants to estimate the mean age of all students enrolled at a college. The estimate must be within one year of the population mean. Assume the population of ages is normally distributed. Determine the minimum …
3. Statistics

An admissions director wants to estimate the mean age of all students enrolled at a college. The estimate must be within one year of the population mean. Assume the population of ages is normally distributed. Determine the minimum …
4. college

Find the 90% confidence interval for the variance and the standard deviation of the ages of seniors at Oak Park College if a sample of 24 students has a standard deviation of 2,3 years. Assume the variable is normally distribution
5. statistics

If the ages of colleges students are normally distributed with a mean of 27 years and a standard deviation of 3.4, what is the probability that a sample of 34 students would have an average age of at least 25.6 years
6. statistics

The data below are the ages of a random sample of 8 men in a bar. It is known that the population of ages are normally distributed with a standard deviation of 11. Determine the 93% confidence interval estimate of the population mean. …
7. stats

The president of a large university wishes to estimate the average age of the students presently enrolled. From past studies, the standard deviation ó is known to be 2 years. A sample of 50 students is selected and the mean is found …
8. STATISTICS

A random sample of stock prices per share (in dollars) is shown. Find the 90% confidence interval for the variance and standard deviation for the prices. Assume the variable is normally distributed.
9. Math Statistics

5. Students in an introductory statistics class were asked to report the age of their mothers when they were born. Summary statistics include Sample size: 36 students Sample mean: 29.643 years Sample standard deviation: 4.564 years …
10. Statistics

QUESTION 1 Use the following scenario and data for all the questions The lives of Lithium batteries used in a type of cell phones are normally distributed with an unknown standard deviation. A simple random sample of equation batteries …

More Similar Questions