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A research hospital tries a new antibiotic scrub before surgery to see whether it can lower the rate of infections of surgical sites. The old rate of infection is \(4 \%\). The null hypothesis is that the proportion of infections is \(0.04, p=0.04\). Give the alternative hypothesis in words and symhols

Short Answer

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The alternative hypothesis, in words, is that the new antibiotic scrub will decrease the rate of post-surgery infections. In symbols, it is represented by \(p < 0.04\).

Step by step solution

01

Understand the Null Hypothesis

In this context, the null hypothesis (H0) is the statement that the proportion of infections after surgery, when using the new antibiotic scrub, remains the same as the old rate, i.e., \(p = 0.04\) or 4%.
02

Know What is Alternative Hypothesis

An alternative hypothesis (Ha) is the counterpart to the null hypothesis and presents a statement that will be accepted in the event that the null hypothesis is rejected after statistical testing.
03

Formulate the Alternative Hypothesis

In this case, since the research hospital is trying out a new antibiotic scrub, the expectation is that it lowers the infection rate. Therefore, the alternative hypothesis would state - The proportion of infections after surgery when using the new antibiotic scrub is less than 4%, i.e., \(p < 0.04\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Statistical Testing
Statistical testing is a fundamental process in research used to determine whether a hypothesis can be accepted or rejected. It involves the collection and analysis of data to draw conclusions about populations.
The procedure typically starts with defining two hypotheses:
  • Null Hypothesis ( H_0 ): A statement asserting that there is no effect or difference.
  • Alternative Hypothesis ( H_a ): A statement that contradicts the null hypothesis, suggesting a new effect or difference exists.
After hypothesis formation, data is gathered through experiments or observations. Statistical tests are then conducted to determine the probability of the data supporting the null hypothesis.
The results of these tests lead us to either reject the null hypothesis in favor of the alternative, or fail to reject the null hypothesis, maintaining simplicity in conclusion. Common statistical tests include t-tests, chi-square tests, and ANOVA.
Proportion Comparison
Proportion comparison in statistics is about comparing proportions from two or more groups to determine if significant differences exist. This is especially important in fields such as medicine and social sciences.
The process begins with calculating the proportion of a characteristic within a group, often expressed as a percentage. For example, if 4% of surgeries result in infections, the proportion is 0.04.
Proportion comparison answers questions like whether a new treatment reduces infection rates or if men and women differ in their response to a drug.
  • Statistical tests such as the z-test for proportions can help in comparing these proportions.
  • By calculating the test statistic, researchers can determine whether observed differences are statistically significant.
Proportion comparisons are critical for making informed decisions in practice, particularly in healthcare for evaluating treatment efficacy, like the antibiotic scrub in surgeries.
Infection Rate Reduction
Infection rate reduction is a crucial goal in healthcare, especially in surgical settings where infections can complicate recovery. Reducing infection rates often involves new treatments or protocols like antibiotic scrubs.
To evaluate the effectiveness of such interventions, researchers set up a hypothesis test. The null hypothesis would assert no reduction, implying that the new intervention has no effect.
If data suggests fewer infections with the new intervention, this supports the alternative hypothesis of a reduction in the infection rate.
  • The goal is to provide compelling evidence that the new method decreases the chance of infection.
  • Effectiveness is often measured by comparing the proportions of infection rates before and after the intervention.
Infection rate reduction not only improves patient outcomes but also reduces healthcare costs by minimizing complications. This is why rigorous statistical testing and hypothesis validation are critical before implementing any new healthcare procedures.

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Most popular questions from this chapter

A statistician studying ESP tests 500 students. Each student is asked to predict the outcome of a large number of dice rolls. For each student, a hypothesis test using a \(10 \%\) significance level is performed. If the p-value for the student is less than or equal to \(0.10\), the researcher concludes that the student has ESP. Out of 500 students who do not have ESP, about how many could you expect the statistician to declare do have ESP?

A new food supplement is being tested to see whether it can reduce obesity in the population of concern. At present, the percentage of obese people is \(60 .\) The null hypothesis is that \(p\) (the proportion of the population using the food supplement that is still obese) is \(0.60 .\) Pick the correct alternative hypothesis. i. \(p \neq 0.60\) ii. \(p<0.60\) iii. \(p>0.60\)

In the mid-1800s, Dr. Ignaz Semmelweiss decided to make doctors wash their hands with a strong disinfectant between patients at a clinic with a death rate of \(9.9 \%\). Semmelweiss wanted to test the hypothesis that the death rate would go down after the new hand-washing procedure was used. What null and alternative hypotheses should he have used? Explain, using both words and symbols. Explain the meaning of any symbols you use.

Mercury in Freshwater Fish (Example 11) Some experts believe that \(20 \%\) of all freshwater fish in the United States have such high levels of mercury that they are dangerous to eat. Suppose a fish market has 250 fish tested, and 60 of them have dangerous levels of mercury. Test the hypothesis that this sample is not from a population with \(20 \%\) dangerous fish. Use a significance level of \(0.05\). Comment on your conclusion: Are you saying that the percentage of dangerous fish is definitely \(20 \%\) ? Explain.

A magazine advertisement claims that wearing a magnetized bracelet will reduce arthritis pain in those who suffer from arthritis. A medical researcher tests this claim with 233 arthritis sufferers randomly assigned either to wear a magnetized bracelet or to wear a placebo bracelet. The researcher records the proportion of each group who report relief from arthritis pain after 6 weeks. After analyzing the data, he fails to reject the null hypothesis. Which of the following are valid interpretations of his findings? There may be more than one correct answer. a. The magnetized bracelets are not effective at reducing arthritis pain. b. There's insufficient evidence that the magnetized bracelets are effective at reducing arthritis pain. c. The magnetized bracelets had exactly the same effect as the placebo in reducing arthritis pain. d. There were no statistically significant differences between the magnetized bracelets and the placebos in reducing arthritis pain.

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