Sunday

April 20, 2014

April 20, 2014

Posted by **carl** on Monday, May 14, 2012 at 9:33am.

115, 128, 107, 109, 116, 124, 135

127, 115, 104, 118, 126, 129, 133

- stat -
**MathGuru**, Monday, May 14, 2012 at 7:01pmNull and alternative hypotheses:

Ho: The population standard deviation is = 15

Ha: The population standard deviation is < 15

Data given:

sample standard deviation = ? (Note: standard deviation is the square root of the variance; therefore, variance is standard deviation squared).

level of significance = 0.10

n = 14

Calculate the standard deviation from the data given.

The test statistic used in making a decision is the chi-square.

Here's the formula:

chi-square = (sample size - 1)(sample variance)/(value specified in the null hypothesis)

Note: Convert both standard deviations to variances when working with the formula.

Degrees of freedom is equal to n - 1, which is 13.

Checking a chi-square table using alpha = 0.10 with 13 degrees of freedom, find the critical value.

If the test statistic exceeds the critical value from the chi-square table, then the null is rejected and you can accept the alternative hypothesis. If the test statistic does not exceed the critical value from the table, then the null cannot be rejected and you cannot conclude a difference.

I hope this will help get you started.

**Related Questions**

Statistics - assume that adults have IQ scores that are normally distributed ...

statistics - assume that adults have IQ scores that are normally distributed ...

Math - The IQ scores are normally distributed with a mean of 100 and a SD of 15...

Math check - IQ scores in a certain population are normally distributed with a ...

math - It has been found that the average IQ score of students is 115 with a ...

stats - Test scores on a university admissions test are normally distributed, ...

statistics - The Intelligence Quotient (IQ) test scores for adults are normally ...

math - In a large population of adults, the mean IQ is 112 with a standard ...

statistics - IQ scores are normally distributed with a mean u = 100 and a ...

statistics - assume adults have an IQ score that are normally distrubted with a ...