For Exercises 5–8: (a) State the null hypothesis and the alternate hypothesis. (b) State the decision rule. (c) Compute the value of the test statistic. (d) What is your decision regarding H0? (e) What is the p-value? Interpret it.
5. The manufacturer of the X-15 steel-belted radial truck tire claims that the
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Statistical Techniques in Business and Economics
- Investigators are trying to determine if the contamination of a town well led to significant increases in adverse health effects. During the period of time when water was consumed from this contaminated well, there were 16 birth defects among 414 births. After this well was shut off, there were 3 birth defects among 228 births. You asked to determine if the rate of birth defects was higher when the contaminated well was in use. a. Test the claim that the contaminated well was not associated with a change in the rate of birth defects in the community at the alpha = 0.05 level, by using the two-proportion z test. Confirm your answers using Stata. b. Calculate a 95% confidence interval for the true difference between the proportions of birth defects when the contaminated well was in use versus when the well was shut down. c. Construct the 2x2 contingency table representing the data to Calculate the odds of a birth defect when the contaminated water was consumed and when the well was shut…arrow_forwardShort Answer and SPSS K1. Oodles of Noodles, an artisanal noodle manufacturing company in Brooklyn, makes three kinds of handmade, organic, ethically sourced noodles; Thick, Medium and Thin. They are interested in determining which noodle people tend to prefer and which one has the best "mouth feel" as it is referred to in the food industry. They consult with you (as a statistical expert) to collect data from their consumers. You devise a pleasantness rating scale for the noodles with 1 being the most pleasant to 5 being the least pleasant (so that lower scores indicate better "mouth feel"). You randomly assign 60 individuals to one of three separate groups. Twenty individuals taste and rate the thick noodles, another twenty individuals rate the medium noodles, and another twenty individuals rate the thin noodles. The data for this question can be found in the file labeled "Noodles" on BB. (20 points) (FYI, I like thinner noodles, think Ramen or angel hair pasta, what about you?) Using…arrow_forwardwoman loves, as everyone should, to collect and analyze statistical information. He wishes to find a relationship between how many hours students study and how they do on their statistics tests. He takes a random sample of 16 students at Ideal U., asks how many hours they studied for a university-wide stat testand how they did on the test, enters the data into a computer for analysis and presents the results below. ANALYSIS OF HOURS AND GRADES (n = 16): Descriptive Statistics: HOURS GRADES Mean: 4.2 75.8 Mode: 5.0 79.0 St. Dev: 2.3 10.1 Quartiles: Q0 2.0 34.0 Q1 3.2 53.7 Q2 4.7 78.5 Q3 6.3 86.9 Q4 9.0 97.0 Regression Analysis: Reg. Eq. is: GRADE = 16.9 + 9.025*HOURS Rsquared = .985 std error = 0.027 F = 8.52 p = .018 What is the correlation between hours studied and grades? a. 0.016 b. 0.992 c. 0.985 d. cannot be determined e. 0.12arrow_forward
- You take a survey that is supposed to measure whether you are an extrovert or not. The score you get on the extrovert survey is a z-score of 2.0. What does that mean about your level of extraversion compared to the average score?arrow_forwardIs the average time to complete an obstacle course shorter when a patch is placed over the right eye than when a patch is placed over the left eye? Thirteen randomly selected volunteers first completed an obstacle course with a patch over one eye and then completed an equally difficult obstacle course with a patch over the other eye. The completion times are shown below. "Left" means the patch was placed over the left eye and "Right" means the patch was placed over the right eye. Time to Complete the Course Right 43 50 42 48 50 50 47 48 Left 44 50 42 53 48 53 47 48 Assume a Normal distribution. What can be concluded at the the a = 0.10 level of significance level of significance?arrow_forwardDo people walk faster in the airport when they are departing (getting on a plane) or do they walk faster when they are arriving (getting off a plane)? A reputable researcher measured the walking speed of random travelers in two International Airports. His findings are summarized in the table. Complete parts (a)-(c) below. EEE Click the icon to view the findings. O A. This is an observational study since the researcher influenced the data Walking Speed O B. This is a designed experiment since the researcher influenced the data. O C. This is a designed experiment since the researcher did not influence the data. Direction of Travel Departure 251 Arrival O D. This is an observational study since the researcher did not influence the data. Mean speed (feet per minute) Standard deviation (feet per minute) Sample size 274 (b) Explain why it is reasonable to use Welch's t-test. 45 38 O A. The populations are normally distributed. O B. The samples are random, large and independent 35 35 O C. The…arrow_forward
- (d) Use the t-test to find the standardized test statistic t.arrow_forwardman loves, as everyone should, to collect and analyze statistical information. He wishes to find a relationship between how many hours students study and how they do on their statistics tests. He takes a random sample of 16 students at Ideal U., asks how many hours they studied for a university-wide stat test and how they did on the test, enters the data into a computer for analysis and presents the results below. ANALYSIS OF HOURS AND GRADES (n = 16): Descriptive Statistics: HOURS GRADES Mean: 4.2 75.8 Mode: 5.0 79.0 St. Dev: 2.3 10.1 Quartiles: Q0 2.0 34.0 Q1 3.2 53.7 Q2 4.7 78.5 Q3 6.3 86.9 Q4 9.0 97.0 Regression Analysis: Reg. Eq. is: GRADE = 16.9 + 9.025*HOURS Rsquared = .985 std error = 0.027 F = 8.52 p = .018 What is the median number of hours studied? a. 2.3 b. 4.7 c. 4.5 d. 4.2 e. 5.5 f. 5 g. cannot be determinedarrow_forwardTaylor Swift is interested in learning what proportion of her fans want her to re-record her masters, so she takes a simple random sample of 500 fans and asks them. Of the 500 fans, 487 of them (97.4%) respond that they want her to re-record all of her masters. What is the parameter and what is its value? a. The parameter is the average number of all Taylor Swift fans who want her to re-record her masters, which is unknown. b. The parameter is the proportion of the sampled Taylor Swift fans who want her to re-record her masters, which is unknown. c. The parameter is the group of the sampled Taylor Swift fans who want her to re-record her masters, which is 487. d. The parameter is the proportion of the sampled Taylor Swift fans who want her to re-record her masters, which is 0.974. e. The parameter is the proportion of all Taylor Swift fans who want her to re-record her masters, which is unknown. f. The parameter is the proportion of all…arrow_forward
- man loves, as everyone should, to collect and analyze statistical information. He wishes to find a relationship between how many hours students study and how they do on their statistics tests. He takes a random sample of 16 students at Ideal U., asks how many hours they studied for a university-wide stat test and how they did on the test, enters the data into a computer for analysis and presents the results below. ANALYSIS OF HOURS AND GRADES (n = 16): Descriptive Statistics: HOURS GRADES Mean: 4.2 75.8 Mode: 5.0 79.0 St. Dev: 2.3 10.1 Quartiles: Q0 2.0 34.0 Q1 3.2 53.7 Q2 4.7 78.5 Q3 6.3 86.9 Q4 9.0 97.0 Regression Analysis: Reg. Eq. is: GRADE = 16.9 + 9.025*HOURS Rsquared = .985 std error = 0.027 F = 8.52 p = .018 We know that 25% of all the grades falls into which of these regions? a. 78.5 to 79.0 b. 78.5 to 86.9 c. 75.8 to 86.9 d. 75.8 to 97.0 e. 78.5 to 97.0 f. 75.8 to 79.0arrow_forwardman loves, as everyone should, to collect and analyze statistical information. He wishes to find a relationship between how many hours students study and how they do on their statistics tests. He takes a random sample of 16 students at Ideal U., asks how many hours they studied for a university-wide stat test and how they did on the test, enters the data into a computer for analysis and presents the results below. ANALYSIS OF HOURS AND GRADES (n = 16): Descriptive Statistics: HOURS GRADES Mean: 4.2 75.8 Mode: 5.0 79.0 St. Dev: 2.3 10.1 Quartiles: Q0 2.0 34.0 Q1 3.2 53.7 Q2 4.7 78.5 Q3 6.3 86.9 Q4 9.0 97.0 Regression Analysis: Reg. Eq. is: GRADE = 16.9 + 9.025*HOURS Rsquared = .985 std error = 0.027 F = 8.52 p = .018 What problem might there be in using the regression model to predict what grade a student might get if they studied 10 hours? a. The predicted grade for 10 hours is more than 100, which is impossible. b. The value of 10…arrow_forwardQ.1 Dr. Star is interested in whether the physical coordination skills among low-income pre-school children are different from those of other children. She knows the population mean for the Pre- School Coordination Activity Test (PCAT) is 120 with o x= 10. She tests 80 preschoolers from low-income families and obtains an X= 122. a. Should Dr. Star do a one-tailed or a two-tailed test? Explain your answer. b. State the appropriate H o and H a , given your answer in part a. c. Use at a = 0.05. What is the value of zcrit ? d. Calculate z obt e. Using symbols, report your findings. f. What should Dr. Star conclude?arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillHolt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGAL