Tomatoes II The chapter also described a completely randomized two-factor experiment testing OptiGro fertil-izer in conjunction with two different routines for water-ing the plants. Describe a strategy to randomly assign the 24 tomato plants to the six treatments.

Twenty university students chosen at random from students enrolled at Carthage College took part in an experiment testing the effect of watching ABC News versus CNN on knowledge of world events. The 20 participants were divided randomly into two equal groups of 10 students each. One group was assigned to watch ABC and the other was assigned to watch CNN. Participants then watched their assigned station (ABC or CNN) for 3 hours a night for 4 weeks. At the end of the 4 week period they were administered a test of world knowledge. The results were as follows: XbarABC = 104; sABC = 12 XbarCNN = 99; sCNN = 10 Compute the 95% confidence interval around the difference between the two groups.

The improved crop varieties are evaluated at farmers fields before their release for a large scale production. The claim made by a chickpea breeder is that, on average, her improved variety produces higher yield of chickpea compared to the local variety grown by farmers in her region. To examine her claim, the improved variety of chickpea was evaluated at 25 randomly selected farmer-fields (farms) in that region. Each field was divided into two parts, one part of the field was randomly assigned to the improved variety to be grown under a crop management practice recommended for this variety, and the other part to the local variety with an ongoing practice followed for it. You may note there were 25 different fields and the two varieties were grown within each of them. The chickpea yields of the two varieties were measured, in kg per hectare, from each of the fields. The following R- code outputs contain the information that you may use to answer the questions. The data vectors,…

The Salk vaccine against polio was tested in 1954 in a carefully designed field experiment. Approximately, 400,000 children took part in this experiment. Using a randomization procedure, the children were randomly divided into 2 groups of equal size, a treatment group, and a control group. The vaccine was given only to the children in the treatment group; the control group children received placebo injections. The children did not know which of the two groups they had been placed into. The diagnosticians also lacked this information. 57 children in the treatment group went on to contract polio, while 142 children in the control group contracted the illness. How likely would such a difference in outcomes be when the assignment to the treatment or control group had absolutely no effect on the outcomes?

The manufacturer of a new racecar engine claims that the proportion of engine failures due to overheating for this new engine, (p1), will be no higher than the proportion of engine failures due to overheating of the old engines, (p2). To test this statement, NASCAR took a random sample of 115 of the new racecar engines and 120 of the old engines. They found that 12 of the new racecar engines and 9 of the old engines failed due to overheating during the test. Does NASCAR have enough evidence to reject the manufacturer's claim about the new racecar engine? Use a significance level of α=0.1 for the test. Step 1 of 6 :   State the null and alternative hypotheses for the test.   Step 2 of 6 :   Find the values of the two sample proportions, pˆ1p^1 and pˆ2p^2. Round your answers to three decimal places.     Step 3 of 6 :   Compute the weighted estimate of p, p‾p‾. Round your answer to three decimal places.   Step 4 of 6 :   Compute the value of the test…

A sporting goods manufacturing company wanted to compare the distance traveled by golf balls produced using four different designs.  Nine balls were manufactured with each design and were brought to the local golf course for the club professional to test.  The order in which the balls were hit with the same club was randomized to the pro did not know which type of ball was being hit.  All 36 balls were hit (assuming the environmental conditions played no role).  The resulting distances in yards were recorded and are shown in the following table:   Design 1 Design 2 Design 3 Design 4 206.32 217.08 226.77 230.55 207.94 221.43 224.79 227.95 206.19 218.04 229.75 231.84 204.45 224.13 228.51 224.87 209.65 211.82 221.44 229.49 203.81 213.90 223.85 231.10 206.75 221.28 223.97 221.53 205.68 229.43 234.30 235.45 204.49 213.54 219.50 228.35   Write a set of hypotheses to test the mean…

Some researchers have conjectured that stem-pitting disease in peach tree seedlings might be controlled with weed and soil treatment. An experiment was conducted to compare peach tree seedling growth with soil and weeds treated with one of two herbicides. In a field containing 20 seedlings, 10 were randomly selected from throughout the field and assigned to receive Herbicide A. The remaining 10 seedlings were to receive Herbicide B. Soil and weeds for each seedling were treated with the appropriate herbicide and at the end of the study period the height (in centimeters) was recorded for each seedling. A box plot of each data set showed no indication of non-Normality. The following results were obtained: (cm) s (cm) Herbicide A Herbicide B 94.5 109.1 10 A 95% confidence interval for uB - HA is given by which of the following expressions? (Use the conservative value for degrees of freedom.) 102 9? (109.1- 94.5) t 1.96. 102 92 (109.1- 94.5) + 2.262. 9 10 (109.1- 94.5) + 1.96, 10 V 10 102…

The manufacturer of a new racecar engine claims that the proportion of engine failures due to overheating for this new engine, (p1), will be no higher than the proportion of engine failures due to overheating of the old engines, (p2). To test this statement, NASCAR took a random sample of 135 of the new racecar engines and 175 of the old engines. They found that 14 of the new racecar engines and 8 of the old engines failed due to overheating during the test. Does NASCAR have enough evidence to reject the manufacturer's claim about the new racecar engine? Use a significance level of α=0.01 for the test. Step 3 of 6 :   Compute the weighted estimate of p, p‾. Round your answer to three decimal places.

In a large clinical​ trial, 401,321 children were randomly assigned to two groups. The treatment group consisted of 201,186 children given a vaccine for a certain​ disease, and 30 of those children developed the disease. The other 200,135 children were given a​ placebo, and 100 of those children developed the disease. Consider the vaccine treatment group to be the first sample. Identify the values of n1​, p1​, q1​, n2​, p2​, q2​, p​, and q. = Round each to 8 decimals