Psychology 60, Fall 2016 Name: ____________________________ Homework #6 ID#: ____________________________

Due in class Tuesday, November 15th

(All of the above information is required.)

1) [ 2 pts. ] What is the difference between a Type I error and a Type II error?

Define both. 2) [ 2 pts. ] What are four factors that influence statistical power?

3) [ 1 pt. ] What should you be cautious about if you reject Ho with an extremely large sample size?

4) [ 6 pts. ] You are in charge of quality control for the company that produces the new, “super-healthy” sports drink Iguana-aid. The three main ingredients in this drink are water (which is known to be important for good health), high-fructose corn syrup, and Industrial Green Dye #3702 (which is guaranteed to be healthier than Industrial Green Dye #3701 :-). If all the production machines in the factory are functioning properly, then the amount of high-fructose corn syrup (HFCS) in the population of Iguana-aid bottles should have a mean of 345 mg. To ensure that there are no malfunctions, every month you collect and test a random sample of 30 bottles of Iguana-aid. This month, the mean amount of HFCS in your sample is 320 mg, with a sample standard deviation of 20. Conduct the appropriate hypothesis test, at = .05, to gain insight into whether the mean amount of HFCS in this month’s batch of Iguana-aid is significantly different (in a purely statistical rather than practical sense) from 345 mg. Provide the information indicated below:

a) Statistical Hypotheses b) Decision Rule v) Calculations d) Decision e) Interpretation

5) [ 7 pts. ] Suppose that local police are interested in determining whether the average speed of cars in a local intersection exceeds the local speed limit of 40 mph. They measure the speed (in mph) of 10 randomly selected cars passing through that intersection and collect the following data: 45, 59, 53, 50, 45, 49, 53, 38, 62, 73 Showing all necessary computations, conduct the appropriate hypothesis test, at = .05, to determine whether the average speed of cars in this intersection exceeds 40 mph.

Provide the information indicated below:

a) Statistical Hypotheses b) Decision Rule c) Calculations d) Decision e) Interpretation f) What must you assume when applying the test in this case?