PLSC 724 - PRACTICE TEST ONE 1. Discuss briefly the relationship between the shape of the normal curve and the variance. 2. What is the relationship between a statistic and a parameter?3. How is the α level related to the probability of a type 1 error?4. The most common levels of significance used in statistical tests are the 5% and 1% levels. Why are levels such as 0.1% or 0.01% not used? 5. Changing α from .05 to .01 causes β to a) remain the same, b) increase, or c) decrease (choose the correct answer). 6. From the standpoint of types of error, what is β? 7. List two ways in which β can be reduced? 8. What is meant by the `power of the test` (in addition to being equal to 1 - β)? 9. How can the power of the test be increased, while keeping α constant? 10. List two of the first three considerations to be made in planning an experiment. 11. Assume you are going to test five different feed rations on fattening steers. You put four steers in each of twenty pens. Four repetitions of each ration are assigned to the twenty pensat random. a) Define an experimental unit; b) what, specifically, is an experimental unit in theabove illustration? How many experimental units are there? c) What are the degrees of freedom for the sources of variation other than treatments? d) What is the numerical value for the denominator when calculating the standard error of a difference between two means? 12. A pharmaceutical company manufactures a pill that is said to contain 50 mg of a certain compound, together with some non-medical carrier to make it taste good. From a statistical standpoint, what does the number 50 represent? 13. Assume you have seven tractors and you want to measure differences in gas consumption while pulling a plow through soil for a specified distance. What are the experimental units? 14. Choose a subject matter area with which you are familiar and illustrate what an experimental unit is. 15. Experiments can be placed into three categories (or types), name them.16. List one means of `error control`. 17. What are two functions of replication? 18. What is the main reason most people do not use more replicates than they do? 19. In replicated experiments, we attempt to maximize the available variation (among, within) thereplicates (choose one). 20. In field experiments, what is considered to be the best shape for the replicates? 21. What effect does the number of replicates have on the standard error of a mean? 22. Define experimental error. 23. Define sampling error. 24. Let t = 2 and r = 3 in a CRD. Illustrate precisely what contributes to experimental error. 25. What is the function of randomization? 26. Show and tell how to randomize a CRD where t = 4 and r = 3. If you planned to take two samples per experimental units, how would this affect the randomization procedure? 27. Assume you have a CRD with sampling. Show, using the `dot` notation, symbols for a) the grand total, and b) a treatment total. 28. Using the following five numbers: 2, 5, 7, 7, 9, compute the variance of a mean. 29. Assume you are comparing two treatments with a paired comparison test. Which of the following sets of hypotheses are valid? There may be more than one answer. a) null hypothesis: μ 1 = μ 2 + 10 alternate hypothesis: μ 1 does not equal μ 2 b) null hypothesis: μ 1 = or > μ 2 alternate hypothesis: μ 1 < μ 2 c) null hypothesis: μ 1 = μ 2 alternate hypothesis: μ 1 does not equal μ 2 d) null hypothesis: μ 1 = μ 2 alternate hypothesis: μ 1 minus μ 2 does not equal 0 30. It is hypothesized that treatment A will `yield` 10 units more than treatment B. If you are to test this hypothesis against the alternative that trt. A exceeds trt. B by more than 10 units, what should you have for the null and alternate hypothesis?31. Given that 1Y 16 and = 22, 2Yand the LSD =7.3, should you accept or reject the null hypothesis of no difference between means? 32. If 1Y 30 and 2Y 52, should the null hypothesis of μ1 + 15 = μ2 be accepted or rejected if tabular `t`= 2.06 and21YYss 4? 33. What is the formula for the least significant difference? 34. What is the basic difference between the LSD and Tukey’s test? 35. Given the following data, calculate the standard error of a difference (i.e.21YYss  ) between treatment means. SOV df SSTreatments 4 2304Experimental Error 15 960Sampling Error 20 320 36. If you were to calculate the LSD from data in problem 35, how many degrees of freedom would the tabular `t` have? 37. Assume you are using the F-test to compare treatment mean square with error mean square. Is this a one or two tailed F-test? 38. Under what two conditions is the CRD most appropriate? 39. Assume you have six weed control chemicals to evaluate on one variety of wheat under field conditions at Fargo. What would be the most important point to consider relative to possible uses of the CRD? 40. Write the linear model for an individual observation and define each term, for a CRD with sampling. 41. In a CRD, what is the formula for the standard error of a difference between two treatment means when ri ≠ rj.42. Given a CRD with 5 treatment, 3 repetitions of