Answer
The hypotheses are:
- \( H_{0}: p = 0.20 \)
- \( H_{a}: p < 0.20 \)
The sample proportion is \( \hat{p} = 0.1818 \).
The test statistic is \( z = -1.734 \).
The p-value is approximately 0.0418.
Since the p-value (0.0418) is less than the significance level (0.10), we reject the null hypothesis. This means there is enough evidence to conclude that Delaware has a lower proportion of identity theft than 20%.
Solution
To determine if the data provides enough evidence to show that Delaware has a lower proportion of identity theft than 20%, we need to test the hypothesis at the 10% level.
Given:
- Total complaints in Delaware: 1452
- Complaints of identity theft in Delaware: 264
- National proportion of identity theft complaints: 20% (0.20)
Hypotheses:
\( H_{0}: p = 0.20 \) (The proportion of identity theft complaints in Delaware is equal to the national proportion)
\( H_{a}: p < 0.20 \) (The proportion of identity theft complaints in Delaware is less than the national proportion)
Sample proportion:
\( \hat{p} = \frac{264}{1452} \approx 0.1818 \)
Test statistic:
\( z = \frac{\hat{p} - p}{\sqrt{\frac{p(1-p)}{n}}} \)
where \( n = 1452 \) and \( p = 0.20 \)
Substitute the values into the formula to calculate the test statistic:
\( z = \frac{0.1818 - 0.20}{\sqrt{\frac{0.20(1-0.20)}{1452}}} \)
Calculate the test statistic:
\( z \approx -1.734 \)
Now, we need to find the p-value associated with the test statistic. The p-value represents the probability of observing a test statistic at least as extreme as the one we obtained, assuming that the null hypothesis is true.
The p-value is the probability of observing a z-score less than -1.734, which can be found using a standard normal distribution table or calculator.
After calculating the p-value, we can compare it to the significance level (10%) to determine if the data provides enough evidence to reject the null hypothesis.
Calculate the value by following steps:
- step0: Calculate:
\(0.1818-0.2\)
- step1: Subtract the numbers:
\(-0.0182\)
Calculate or simplify the expression \( \sqrt{\frac{0.20(1-0.20)}{1452}} \).
Calculate the value by following steps:
- step0: Calculate:
\(\sqrt{\frac{0.2\left(1-0.2\right)}{1452}}\)
- step1: Subtract the numbers:
\(\sqrt{\frac{0.2\times 0.8}{1452}}\)
- step2: Multiply the numbers:
\(\sqrt{\frac{0.16}{1452}}\)
- step3: Divide the terms:
\(\sqrt{\frac{1}{9075}}\)
- step4: Use the properties of radicals:
\(\frac{\sqrt{1}}{\sqrt{9075}}\)
- step5: Simplify the expression:
\(\frac{1}{55\sqrt{3}}\)
- step6: Multiply by the Conjugate:
\(\frac{\sqrt{3}}{55\sqrt{3}\times \sqrt{3}}\)
- step7: Multiply the numbers:
\(\frac{\sqrt{3}}{165}\)
Calculate or simplify the expression \( \frac{0.1818 - 0.20}{\sqrt{\frac{0.20(1-0.20)}{1452}}} \).
Calculate the value by following steps:
- step0: Calculate:
\(\frac{0.1818-0.2}{\sqrt{\frac{0.2\left(1-0.2\right)}{1452}}}\)
- step1: Subtract the numbers:
\(\frac{0.1818-0.2}{\sqrt{\frac{0.2\times 0.8}{1452}}}\)
- step2: Multiply the numbers:
\(\frac{0.1818-0.2}{\sqrt{\frac{0.16}{1452}}}\)
- step3: Divide the terms:
\(\frac{0.1818-0.2}{\sqrt{\frac{1}{9075}}}\)
- step4: Simplify the root:
\(\frac{0.1818-0.2}{\frac{\sqrt{3}}{165}}\)
- step5: Subtract the numbers:
\(\frac{-0.0182}{\frac{\sqrt{3}}{165}}\)
- step6: Convert the expressions:
\(\frac{-\frac{91}{5000}}{\frac{\sqrt{3}}{165}}\)
- step7: Multiply by the reciprocal:
\(-\frac{91}{5000}\times \frac{165}{\sqrt{3}}\)
- step8: Reduce the numbers:
\(-\frac{91}{1000}\times \frac{33}{\sqrt{3}}\)
- step9: Multiply the fractions:
\(-\frac{91\times 33}{1000\sqrt{3}}\)
- step10: Multiply:
\(-\frac{3003}{1000\sqrt{3}}\)
- step11: Multiply by the Conjugate:
\(\frac{-3003\sqrt{3}}{1000\sqrt{3}\times \sqrt{3}}\)
- step12: Multiply the numbers:
\(\frac{-3003\sqrt{3}}{3000}\)
- step13: Reduce the fraction:
\(\frac{-1001\sqrt{3}}{1000}\)
- step14: Calculate:
\(-\frac{1001\sqrt{3}}{1000}\)
The test statistic is approximately -1.734.
Now, we need to find the p-value associated with the test statistic. The p-value represents the probability of observing a test statistic at least as extreme as the one we obtained, assuming that the null hypothesis is true.
The p-value is the probability of observing a z-score less than -1.734, which can be found using a standard normal distribution table or calculator.
After calculating the p-value, we can compare it to the significance level (10%) to determine if the data provides enough evidence to reject the null hypothesis.
Reviewed and approved by the UpStudy tutoring team
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