Question

Using the data of UAS accidents decide if procedural/skill errors are = to other errors, what statistical test would you intend to use. Analyze your data to ensure that it meets the assumptions of the test (for example parametric vs. non-parametric).

Table 1

UAS Accidents

UAS Type	Other	Procedural/Skill
Hunter	15	14
Shadow	10	4
Predator	7	7
Global Hawk	2	1

Answer 1

Solution:-

State the hypotheses. The first step is to state the null hypothesis and an alternative hypothesis.

Null hypothesis: ?₁ - ?₂ = 0
Alternative hypothesis: ?₁ - ?₂ ? 0

Note that these hypotheses constitute a two-tailed test. The null hypothesis will be rejected if the difference between sample means is too big or if it is too small.

Formulate an analysis plan. For this analysis, the significance level is 0.05. Using sample data, we will conduct a two-sample t-test of the null hypothesis.

Analyze sample data. Using sample data, we compute the standard error (SE), degrees of freedom (DF), and the t statistic test statistic (t).

SE = sqrt[(s₁²/n₁) + (s₂²/n₂)]
SE = 3.894
DF = 6
t = [ (x₁ - x₂) - d ] / SE

t = 0.51

where s₁ is the standard deviation of sample 1, s₂ is the standard deviation of sample 2, n₁ is the size of sample 1, n₂ is the size of sample 2, x₁ is the mean of sample 1, x₂ is the mean of sample 2, d is the hypothesized difference between the population means, and SE is the standard error.

Since we have a two-tailed test, the P-value is the probability that a t statistic having 6 degrees of freedom is more extreme than -0.51; that is, less than -0.51 or greater than 0.51

Thus, the P-value = 0.63

Interpret results. Since the P-value (0.63) is greater than the significance level (0.05), we have to accept the null hypothesis.