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.
- The Toyota dealership has advertised that oil changes will be completed in 15 minutes or less. Test whether their advertisement is incorrect, on average.
- 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.
- 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:
- Identify H0 and HA. If the question has a context then the parameter should be stated within that context.
- Define the p-value specific to the situation.
- Draw the null distribution (with the p-value shaded).
- Compute the p-value. [*Show your `distrib()` code.*]
- 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.
- HA: μ>75, σ=12, n=50, x̄=79.5, α=0.10.
- HA: μ<15000, σ=8000, n=50, x̄=13700, α=0.10.
- HA: μ≠14, σ=6, n=25, x̄=11.2, α=0.05.