6.52 What’s wrong? Here are several situations where there is an incorrect application of the ideas presented in this section. Write a short paragraph explaining what is wrong in each situation and why it is wrong.

1. (a) A researcher tests the following null hypothesis: H₀: .

2. (b) A random sample of size 30 is taken from a population that is assumed to have a standard deviation of 5. The standard deviation of the sample mean is 5/30.

3. (c) A study with reports statistical significance for H_a: μ > 50.

4. (d) A researcher tests the hypothesis H₀: μ = 350 and concludes that the population mean is equal to 350.