# Statistics

posted by .

A statistics practitioner determined that the mean and standard deviation of a data set were 120and 30, respectively. What can you say about the proportions of observations that lie between each of the following intervals?

a. 90 and 150
b. 60 and 180
c. 30 and 210

• Statistics -

Z = (score-mean)/SD

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

• Statistics -

## Similar Questions

1. ### statistics

Given a distribution with mean X and standard deviation S, answer the following. 4.1 Determine the mean and standard deviation if constant K is added to each observation 4.2 Determine the mean and standard deviation if constant K is …
2. ### statistics

A statistics practitioner formulated the following hypothesis: Ho: population mean=200 H1: population mean<200 sample mean=190 n=9 population standard deviation=50 Calculate the p-value of the test
3. ### stats

A statistics practitioner wishes to test the following hypothesis: H0 : ì = 600 against H1 : ì < 600 A sample of 50 observations yielded the statistics: mean x = 585 and standard deviation sx = 45. The test statistic of a test …
4. ### statistics

I.use the chebyshev's theorem to find out what percentage of the values will fall between 201 and 257 for a data set with a mean of 229 and standard deviation of 14. II. use the emperical rule to find out two values 68% of the data …
5. ### Math-Statistics

I. Use Chebyshev’s theorem to find what percent of the values will fall between 156 and 276 for a data set with a mean of 216 and standard deviation of 12. II. Use the Empirical Rule to find what two values 68% of the data will fall …
6. ### statistics

a. A statistics practitioner randomly sampled 100 observations from a population with a standard deviation of 5 and found that x is 10. Estimate the population mean with 90% confidence.
7. ### statistics

a.a statistics practitioner randomly sampled 100 observations from a population with a standard deviation of 5 and found that x is 10. Estimate the population mean with 90% confidence. Repeat (a) with a sample sixe of 25
8. ### statistics

The mean of a normal probability distribution is 100 and the standard deviation is 8. About what percent of the observations lie between 84 and 116?