The desired percentage of Silicon Dioxide (SiO2) in a certain type of aluminous cement is 5.5. To test whether the true average percentage is 5.5 for a particular production facility, 16 independently obtained samples are analyzed and a sample mean of 5.25 was obtained. Suppose that the percentage of SiO2 in a sample is normally distributed with a sigma of 0.3. Does this indicate conclusively that the true average is smaller than 5.5? Carry the procedure at a 0.01 significance level. Use only the P-Value approach. State H0 and Ha (20 pts)

The true average percentage of Silicon Dioxide (SiO2) is less than 5.5.

Step-by-step explanation:

In this case we need to test whether the true average percentage of Silicon Dioxide (SiO2) in a certain type of aluminous cement is smaller than 5.5.

The hypothesis can be defined as follows:

H₀: The true average percentage of Silicon Dioxide (SiO2) is 5.5, i.e. μ = 5.5.

Hₐ: The true average percentage of Silicon Dioxide (SiO2) is less than 5.5, i.e. μ < 5.5.

The information provided is:

As the population standard deviation is provided, we will use a z-test for single mean.

Compute the test statistic value as follows:

The test statistic value is -3.33.

Decision rule:

If the p-value of the test is less than the significance level then the null hypothesis will be rejected.

Compute the p-value for the two-tailed test as follows:

*Use a z-table for the probability.

The p-value of the test is 0.00043.

p-value = 0.00043 < α = 0.05

The null hypothesis will be rejected at 5% level of significance.

Thus, it can be concluded that the true average percentage of Silicon Dioxide (SiO2) is less than 5.5.