The Weschsler IQ test has a μ =100 and a σ = 15. A vitamin company said if people took vitamin X for 30 days their IQ would improve. A simple random sample of 49 people took the vitamins for 30 days. They then took the IQ test. The mean IQ of the sample was 103.
- What is Ho? What is Ha?
- What is the Z-score? What is the P-value?
- Is the result significant at the 5% level? Why or why not?