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Seminar 33

Seminar 33. Shana Schwarz. Two Types of Error. Type I (i.e. false positive) Occurs by rejecting the null hypothesis even when it is true. In other words, this is the error of accepting an alternative hypothesis (the hypothesis of interest) when the results can be attributed to chance.

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Seminar 33

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  1. Seminar 33 Shana Schwarz

  2. Two Types of Error • Type I (i.e. false positive) • Occurs by rejecting the null hypothesis even when it is true. • In other words, this is the error of accepting an alternative hypothesis (the hypothesis of interest) when the results can be attributed to chance. • occurs when we are observing a difference when in truth there is none.

  3. Two Types of Error • Type II (i.e. false negative) • Occurs by accepting the null hypothesis even when it is wrong. • In other words, this is the error of failing to observe a difference when in truth there is one.

  4. So… What Would the Two Types of Error be in Regard to a Drugs’ Effectiveness? • Type I • Error that occurs when one drug is thought to be more effective then another but is later discovered that there is no difference. • Type II • Error that occurs when two or more drugs are thought to be equivalent in effectiveness and it is later discovered that there is a superior drug.

  5. So… What Would the Two Types of Error be in Regard to a Drugs’ Side Effects? • Type I • Error that occurs when a drug is thought to have side effects but is later discovered that is does not. • Type II • Error that occur when a drug is thought to have no side effects but is later discovered that it does.

  6. Federal Study Finds No Benefits of New Antipsychotic Drug • What is this article taking about? • “Expensive new antipsychotic drugs that are among the most widely prescribed pills in medicine are no more effective and no safer than a older, cheaper drug that has been largely discontinued”.

  7. What Would the Hypothesis’ Be? • Null Hypothesis: H0 • There is no difference in effectiveness between the older, cheaper drugs and the newer more expensive ones. • Alternative Hypothesis: Ha • The newer, more expensive drugs are more effective then the older cheaper ones.

  8. Are We Convinced By This Study? • Indicates in the article that this study is the longest, most comprehensive study ever conducted • Government sponsored study costing over $44 million dollars. • Do you see any reason/ source of error? • I think not because the source interested in the findings is not a privately owned drug company, rather the government and the New England Journal of Medicine.

  9. How Was This Study Conducted? • Technically, the study didn’t measure drug effectiveness rather it measured the amount time a patient stayed on them. • What do you think about this? • I would say this is a poor study design because the drugs’ effectiveness is subjective to the clinician and patients idea of whether or not the benefits outweighed the undesirable effects.

  10. To Decide The Type Of Error… • Focus on the idea that originally drug companies thought these newer, more expensive drugs were more effective then the older, less expensive ones.

  11. What Are The Thoughts On The Matter Now? • Now it is believed after further studies that there are no additional benefits from these newer drugs.

  12. So… What Type of Error is This? • Type I Error • Error that occurs when one drug is thought to be more effective then another but is later discovered that there is no difference.

  13. What are the harmful effects of this type of error? • Patients are spending as much as 5.5 times more money on these newer drugs then they were on the older ones. • Texas Medication Algorithm Project (TMAP) guidelines recommend these drugs as the first line treatment therefore patients incapable of paying for high priced drugs may not be getting any treatment.

  14. Let’s Look At A Few More Things… • Actually, the study’s most shocking discovery is how poorly current anti-psychotic drugs work at all. • Nearly ¾ of people treated stop taking the medication within 18 months because of side effects and/or poor control of symptoms.

  15. What If You Look at the Study Comparing the Two Generations of Drugs’ Side Effects? • What would the hypothesis’ be? • H0 : No difference in the amount/ severity of side effects among the two generations of drugs. • Ha : The newer generation of drugs has less side effects • It was aggressively marketed that the new drugs “caused fewer side effects”. • In fact, this was a false statement, therefore once again there is type I error.

  16. Let’s Look At The Second Article Despite Research, FDA Says Marijuana Has No Benefit

  17. Let’s Review Error Again!

  18. So… What Would the Two Types of Error be in Regard to a Drugs’ Effectiveness? • Type I • Error that occurs when one drug is thought to be more effective then another but is later discovered that there is no difference. • Type II • Error that occur when two or more drugs are thought to be equivalent in effectiveness and it is later discovered that there is a superior drug.

  19. So… What Would the Two Types of Error be in Regard to a Drugs’ Side Effects? • Type I • Error that occurs when a drug is thought to have side effects but is later discovered that is does not. • Type II • Error that occur when a drug is thought to have no side effects but is later discover that it does.

  20. Despite Research, FDA says Marijuana Has No Benefits • What is this article talking about? • The FDA is denying the idea that medicinal marijuana use is beneficial. However, many researchers were left puzzled because they believe that for many patients, medicinal marijuana was extremely helpful. They, the researchers, want additional research to be carried out because they believe that this rejection of its usefulness is politically driven.

  21. What Would the Hypothesis’ Be? • Null Hypothesis: H0 • There are no positive benefits/side-effects to using medicinal marijuana. • Alternative Hypothesis: Ha • Medicinal Marijuana has many positive benefits/side-effects.

  22. Are we convinced by this study • I don’t think that there is convincing evidence that should now cause the rejection of medicinal marijuana use. • FDA spokesperson on this issue is not commenting • Donald Abrams, MD, says that this is a typical report that the government comes out with about every 10 years. • Research on medicinal marijuana is very regulated by the government and therefore, it is difficult to obtain clear results. • It would also be difficult to do a randomized placebo-controlled study because the differences between the substances are obvious.

  23. What Are The Researchers Saying? • “We have found sufficient evidence that smoking marijuana has benefits for some patients”. • It is believed that the FDA decision was based on political pressure from Congress rather then scientific merit. • Positive side-effects/benefits include helping with nausea in chemotherapy patients, increasing appetite and relieving pain in AIDS patients, decreasing depression and making people in the late stages of cancer happier.

  24. How To Go About Determining Type Of Error • Focus on the positive side effects/ benefits to patients who use medicinal marijuana. • The FDA claims that medicinal marijuana is useless, while researchers adamantly believe that their research shows positive benefits and that more research would continue to confirm the idea.

  25. So What Type Of Error Is This? • Type II Error • Error that occur when a drug is thought to have no positive side-effects/benefits but is later discover that it does.

  26. What Is The Harm In This Error? • Many chemo and AIDS patients are not receiving the benefits of decreased nausea and pain, increased appetite, and an overall better mood. • Due to the FDAs position, only eleven states have legalized medicinal use and therefore patients who are prescribed medicinal marijuana can be arrested in any of the other 39 states.

  27. Perhaps A Better Type II Example… • In 2000, Trovan, a drug being prescribed at a rate of 300,000 patients per month was determined to have unforeseen negative side effects one year after is approval by the FDA. • Initial studies approved this drug to safely be used for 14 different uses and no harmful side effects were detected. • Hundreds of people suffered from liver disease and the drug had to immediately be recalled. • Effects of this type of error included many deaths, billions lost by the company who made the drug and numerous lawsuits.

  28. Thanks!! • Have fun in the snow 

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