Question

In: Statistics and Probability

A researcher is reviewing 26 UAS accidents and wants to prove that human error involving unsafe...

A researcher is reviewing 26 UAS accidents and wants to prove that human error involving unsafe acts are mainly due to preconditions. Of the accident information two variables were selected to prove the Hypothesis that preconditions for unsafe acts are a greater factor than unsafe supervision. Using the provided data answer the following and show results of each step.

1. Determine normality

2. What statistical Test is most appropriate

3. Determine if the hypothesis is true

4. What test should you use to show validity of hypothesis results

5. Show all results using either mini tab, excel or stat crunch.

DoD HFACS USAF Accidents
Oranization Influence Unsafe Acts
21 17
1 1
20 3
0 1
3 14
3 1
18 2
3 13
5 9
11 2
2 0
2 5
13 1
8 6

Solutions

Expert Solution

Solution:-

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

Null hypothesis: μ1< μ2
Alternative hypothesis: μ1 > μ2

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

Formulate an analysis plan. For this analysis, the significance level is 0.01. 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 offreedom (DF), and the t statistic test statistic (t).

SE = sqrt[(s12/n1) + (s22/n2)]
SE = 2.493

D.F = 26

t = [ (x1 - x2) - d ] / SE

t = 1.003

where s1 is the standard deviation of sample 1, s2 is the standard deviation of sample 2, n1 is thesize 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 population means, and SE is the standard error.

The observed difference in sample means produced a t statistic of 1.003.

We use the t Distribution Calculator to find P(t > 1.003) = 0.163.

Therefore, the P-value in this analysis is 0.75.

Interpret results. Since the P-value (0.163) is greater than the significance level (0.01), we cannot reject the null hypothesis.


Related Solutions

AAA claims that over 54% of fatal car/truck accidents are caused by driver error, a researcher...
AAA claims that over 54% of fatal car/truck accidents are caused by driver error, a researcher studied 30 randomly selected accidents and found that 14 were caused by driver error. test the AAA claim at a level of significance of a=0.10 H0 H1 CV Test Statistic
Suppose a researcher wants to make sure that the probability of committing a Type I error...
Suppose a researcher wants to make sure that the probability of committing a Type I error is less than 5%. How can the researcher control for this? Set the value for a Type II error at 0.05. Set the alpha level at 0.05. Place the rejection region in both tails. Both setting the alpha level at 0.05 and placing the rejection region in both tails.
A researcher wants to obtain an error of 30 minutes when estimating the hours of sleep...
A researcher wants to obtain an error of 30 minutes when estimating the hours of sleep a student gets at a confidence level of 90%. Use the sample standard deviation from the sleep data and determine the sample size the researcher should use to achieve the desired results. sleep hours per person. 7 7 5 7 6 8 7 8 5 8 8 4 8 8 6 8 8 8 7 10 6 7 8 5 8 7 7 4...
A researcher wants to know whether supplements affect how long vampires can go without requiring human...
A researcher wants to know whether supplements affect how long vampires can go without requiring human blood. She took one sample of vampires (n = 10). Half received a placebo first and the supplement second, while the other half received the sup- plement first and the placebo second. She then recorded how many days the vampires could go without consuming human blood for each condition. The goal of the study was to see whether there would be any difference between...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT