Question

Suppose we are using this data to attempt to pass a quality test in order to market this material.

2.58     2.51     4.04     6.43     1.58     4.32     2.2       4.19    

4.79     6.2       1.52     1.38     3.87     4.54     5.12     5.15

5.5       5.92     4.56     2.46     6.9       1.47     2.11     2.32

6.75 5.84     8.8       7.4       4.72     3.62     2.46     8.75

a. Find a 95% confidence interval for the true mean ignition time using the normal distribution.

b. How would your confidence interval change if you used the t−distribution? Explain.

Answer 1

Let denotes the true mean ignition time.

a) Using normal distribution,

b) Using t distribution,

If one use t distribution, there will not be any significant difference, only the critical value changed slightly.