Identifying Hypotheses

For each research hypothesis or statement below, construct the null and alternative hypotheses (use their respective symbols) and explicitly define the parameter in the hypotheses.

  1. The Toyota dealership has advertised that oil changes will be completed in 15 minutes or less. Test whether their advertisement is incorrect, on average.
  2. The National Institute of Diabetes and Digestive and Kidney Diseases reports that the average cost of bariatric (weight loss) surgery is $22,500. You think that this information is incorrect.
  3. The mean number of murders per burrough in New York City in 2010 was less than 90.

 

Please show these steps (demonstrated in the module reading) when answering all p-value-related questions:
  1. Identify H0 and HA. If the question has a context then the parameter should be stated within that context.
  2. Define the p-value specific to the situation.
  3. Draw the null distribution (with the p-value shaded).
  4. Compute the p-value. [*Show your `distrib()` code.*]
  5. Make a decision about H0. If the question has a context then the conclusion should be stated within that context.


P-Value Calculations and Decisions I

Compute the p-value (see the steps suggested above) and make a decision about H0 for each situation below.

  1. HA: μ>75, σ=12, n=50, x̄=79.5, α=0.10.
  2. HA: μ<15000, σ=8000, n=50, x̄=13700, α=0.10.
  3. HA: μ≠14, σ=6, n=25, x̄=11.2, α=0.05.