There has been a lot of debate over whether the flu vaccine works for old people

Question

There has been a lot of debate over whether the flu vaccine works for old people. All we really know is that 1% of old people die during the 1-2 month flu season. How many of them die because of the flu and how many die because of something else is hard to say. To find out what percent of deaths we can save by the flu shot during flu season, we decide to do a Randomized Controlled Double Blind study. We randomly assign half the subjects to treatment and half the subjects to control. The treatment group gets the real vaccine and the control group gets the placebo before the flu season starts. Then we'll compare the death rate of the 2 groups at the end of flu season. We need to plan how many subjects to assign to each group. As we know that depends on the specific alternative hypothesis we choose and the power of the test. Let's say we're interested in lowering the death rate from 1% to 0.95%. That might sound like a tiny drop but since the elderly population is 46 million, that means 23,000 lives saved! We can use our usual relation: Ha-Hol (IZal+1Zl)SEdifference a. As usual, we'll set the null significance level at 5% and power 80% since most granting agencies wont fund lower powered studies). First calculate zal and Zgl use this calculator or use the standard normal table in the appendix of your notebook) Zal-1.65 Computer's answer now shown above. You are corre Your receipt no. is 150-2793 Previous Tries Zal-0.85 Computer's answer now shown above. You are correct. Your receipt no. is 150-6239 Previous Trios b. The null hypothesis is no difference between the 2 groups, the death rate remains at 196, The alternative hypothesis is that the death rate drops down to 0.95% [Ha-Ho-0.0500 %. puter's answer now shown above. You are correct. ur receipt no. is 150-352 Previous Tries C. Now calculate SEdifference (round to 2 decimal places) SEdifference-0.02 %

Explanation / Answer

A)Z_alpha for alpha =0.05 level of significance is 1.64

power=1-beta,so ,beta=1-0.8=0.2

z_beta for beta =0.2 is 2.05

b)Ha =0.95% and HO=1%
|Ha-Ho|=0.05%
c)SEdifference =(0.05/3.69)%=0.01%

d)now Sd=1% and SDdifference=SD/sqrt(n)

e)therefore total number of subject would be2*10000=20000

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.