# Question

To test the hypothesis that the standard deviation on a standard test is 12, a sample of 40 randomly selected students’ exams was tested. The sample variance was found to be 155. Does this sample provide sufficient evidence to show that the standard deviation differs from 12 at the 0.05 level of significance?

## Answer to relevant Questions

Bright-Lite claims that its 60-watt light bulb burns with a length of life that is approximately normally distributed with a standard deviation of 81 hours. A sample of 101 bulbs had a variance of 8075. Is this sufficient ...It is important that the force required to extract a cork from a wine bottle not have a large standard deviation. Years of production and testing indicate that the no. 9 corks in Applied Example 6.13 (p. 285) have an ...Construct a 95% confidence interval estimate for the mean µ using the sample information n = 24 = 16.7 and s = 2.6 Make a list of four numbers that total “zero.” How many numbers were you able to pick without restriction? Explain how this demonstrates degrees of freedom. Calculate the value of t for the following hypothesis test: Ho: µ = 73 Ha: µ = 73 n = 12 = 71.46 s = 4.1.Post your question

0