A car dealer is interested in comparing the average gas mileages of four different car models. The dealer believes that the average gas mileage of a particular car will vary depending on the person who is driving the car due to different driving styles. Because of this, he decides to use a randomized block design. He randomly selects five drivers and asks them to drive each of the cars. He then determines the average gas mileage for each car and each driver. Can the dealer conclude that there is a significant difference in average gas mileages of the four car models? The results of the study are as follows.  Average Gas Mileage Driver Car A Car B Car C Car D Driver 1 2323 2222 2222 3434 Driver 2 3434 2929 2525 3737 Driver 3 3535 3232 2525 3737 Driver 4 3131 2121 3636 3636 Driver 5 3131 2727 2727 3535 Copy Data ANOVA Source of Variation SSSS dfdf MSMS Rows 120.7000120.7000 44 30.175030.1750 Columns 288.5500288.5500 33 96.183396.1833 Error 175.7000175.7000 1212 14.641714.6417 Total 584.9500584.9500 1919   Copy Data   Step 1 of 3 :   Find the value of the test statistic for testing whether the average gas mileage is the same for the four car models. Round your answer to two decimal places, if necessary

A consumer agency wants to determine which of two laundry detergents, A or B, cleans clothes better. Fifty pieces of fabric are subjected to the same kinds of stains (grass, mud, coffee). Then 25 pieces are randomly assigned to be cleaned with detergent A and the remaining 25 pieces are cleaned with detergent B. After being laundered, the pieces of fabric are rated on a scale from 1–10, with 1 being the least clean to 10 being the most clean. The difference in mean ratings (A – B) was determined to be 1.5. Assuming there is no difference in the two detergents, 200 simulated differences in sample mean ratings are displayed in the dotplot.   Using the dotplot and the difference in mean ratings from the samples, is there convincing evidence that the one detergent is better than the other? Yes, because a difference in mean rating of 1.5 or more occurred only 23 out of 200 times, meaning the difference is statistically significant and there is convincing evidence that A is more effective…

Two different blood pressure medicines are being compared to determine if the average reduction in blood pressure is the same for each medication. The goal of the study is to determine if the medications differ. Twenty men age 50-60 years old are selected for the study. Ten men are chosen at random to receive the first medication and the other 10 men receive the second medication. Each of the 20 men is monitored for one month to determine the change in blood pressure over that time. Minitab provides the 95% confidence interval for (mu1 - mu2) (2.63, 14.18) a. Interpret this 95% CI. b. What assumptions (be specific) are necessary to construct this CI?

In 1940, 2,000 women working in a factory were recruited into a study.  Half of the women worked in manufacturing and half in administrative offices.  The incidence of bone cancer through 1970 among the 1,000 women working in manufacturing was compared with that of 1,000 women working in administrative offices.  Thirty of the women in manufacturing developed bone cancer as compared to 9 of the women in administrative offices.  Identify what type of study this is.

The Bureau of Transportation reports on-time performance for airlines at major airports.  JetBlue, United, and US Airways share Terminal C and Boston's Logan Airport. The percentage of on-time flights reported for a sample month were 76.8% for JetBlue, 71.5% for United, and 82.2% for US Airways. Assume that 30% of the arriving flights at this terminal are JetBlue flights, 32% are United flights, and 38% are US Airways flights. a. Develop a contingency table (table of joint probabilities and marginal probabilities). b. An announcement is made that Flight 1382 will arrive at Terminal C. What is the probability that the flight will arrive on time? c. Flight 1382 arrives on time. What is the probability that Flight 1382 is operated by US Airways?  d. Flight 1382 will not arrive on time. What is the probability that Flight 1382 is operated by United?

An Engineer wanted to know whether the strength of two different concrete mix designs differed significantly. He randomly selected 10 cylinders of each mixture with the following results: Mixture A: 3960, 4090, 3100, 3830, 3200, 3780, 4080, 2940, 4040,3700 Mixture B: 4070, 4890, 5020, 4330, 4640, 5220, 4190, 3730, 4120, 4520 Determine whether mixture B is stronger than mixture A at Alpha = 0.05 level of significance. State the conclusion.

Let’s say a psychologist suspects that emotions affect people’s eating habits, but that the eating habits of anxious people are affected differently. Ten highly anxious subjects are randomly divided into two equal-sized groups, one of which views a horror movie while the other watches a comedy. Ten non-anxious control subjects are similarly divided. The number of ounces of popcorn eaten by each subject during the movie is recorded. ​How many independent variables are there in this design? ​ ​Name each of the factors and levels (using appropriate descriptors from the paragraph): ​How many total conditions (groups) are there in this design? ​Name the dependent variable:

The authors of a paper randomly selected two samples of patients admitted to the hospital after suffering a stroke. One sample was selected from patients who received biofeedback weight training for 8 weeks, and the other sample was selected from patients who did not receive this training. At the end of 8 weeks, the time it took (in seconds) to stand from a sitting position and then to sit down again (called sit-stand-sit time) was measured for the people in each sample. Data consistent with summary quantities given in the paper are given below. For purposes of this exercise, you can assume that the samples are representative of the population of stroke patients who receive the biofeedback training and the population of stroke patients who do not receive this training. Biofeedback Group 2.1 2.8 4.5 2.3 2.9 4.3 3.4 4.2 3.4 3.7 3.0 3.7 3.7 2.5 3.3 No Biofeedback Group 5.2 4.8 4.0 4.3 4.8 4.4 4.3 5.2 3.5 4.3 5.2 4.5 4.1 3.5 4.0   Conduct a test of hypothesis to test whether…

A researcher working at Hershey's is interested in comparing two new chocolate bars: Chocolate Bar A versus Chocolate Bar B. The researcher expects the bars to be different in how much customers will eat per month. The researcher believes the more candy bars someone eats will indicate which one tastes the best. An experiment is designed to compare the two new bars. The number of candy bars eaten by one group of 8 people in a month is measured with Candy Bar A and then the number of candy bars eaten in the same month by another group of 8 participants is measured with Candy Bar B. Use the data below to determine if there is a difference in the consumption of the two candy bars. Candy Bar A Candy Bar B Number of Candy Bars eaten within a month 10, 30, 5, 35, 60, 3, 20, 30, 28, 27, 26, 27, 17, 25 12, 20 With a = .05, determine the critical value of t* that needs to be employed here. The value of the appropriate of t* is: 2.145 O 1.717 2.064 2.819 2.074 O The correct answer is not listed.

Psychologists at Disney World measured factors that affect the scariness of the soundtrack for their Haunted House ride. In particular, they were interested in the loudness of the screams (soft versus loud) and the length of the screams (short versus long). They used a 2 × 2 factorial design to test how these factors combined. They collected data from 10 different riders in each of the four conditions. Each rider rated the scariness of the ride on a nine-point scale. short screams long screams soft screams T=38, n = 10, SS = 13.6 T=64, n = 10, SS = 22.4 loud screams T=52, n=10, SS = 29.6 T=50, n=10, SS = 16.0 For these data: G = 204, N = 40, X2 = 1156. 1. Sketch a dataplot of the mean rating in each condition. 2. Calculate SS total, the total sum of squares 3. Calculate SSwithin, the within-treatments sum of squares. 4. Calculate SSbetween, the between-treatments sum of squares. 5. Calculate SSA the sum of squares for Factor A (length of scream). 6. Calculate SSB, the sum of squares…