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In Exercises 5–20, assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. (Note: Answers in Appendix D include technology answers based on Formula 9-1 along with “Table” answers based on Table A-3 with df equal to the smaller of n1 − 1 and n2 − 1.)
8. Color and Cognition Researchers from the University of British Columbia conducted a study to investigate the effects of color on cognitive tasks. Words were displayed on a computer screen with background colors of red and blue. Results from scores on a test of word recall are given below. Higher scores correspond to greater word recall.
a. Use a 0.05 significance level to test the claim that the samples are from populations with the same mean.
b. Construct a confidence interval appropriate for the hypothesis test in part (a). What is it about the confidence interval that causes us to reach the same conclusion from part (a)?
c. Does the background color appear to have an effect on word recall scores? If so, which color appears to be associated with higher word memory recall scores?
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Elementary Statistics (13th Edition)
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- 6. A population study studied 22,000 male physicians who were assigned to either a low-dose aspirin treatment or a placebo. They followed the physicians for about 5 years and recorded whether or not they had a myocardial infarction (heart attack). The data is presented below. Heart Attack No Heart Attack Aspirin 139 10898 Placebo 239 10795 Note the data is real data from a real study. Conduct a chi-square test (Use = clear about whether this is a Chi-Square Test for Independence or a Chi-Square Test of Homogeneity, and state you conclusions appropriately. 0.05). Be sure you arearrow_forwardI. 6) Suppose that you score 79 on Exam 3. If the average score is 85, and the variance is 23.04, your z-score is: a) 0.26 b) -0.26 c) 1.25 d) -1.25 e) -2.05arrow_forwardTourism is extremely important to the economy of Florida. Hotel occupancy is an often-reported measure of visitor volume and visitor activity (Orlando Sentinel, May 19, 2018). Hotel occupancy data for February in two consecutive years are as follows. Let P₁ = population proportion of rooms occupied for current year P2 = population proportion of rooms occupied for previous year Occupied Rooms Total Rooms 1,360 1,700 1,309 1,700 a. Formulate the hypothesis test that can be used to determine whether there has been an increase in the proportion of rooms occupied over the one-year period. Ho P1 P2 - Select your answer - Ha P₁ P2 - Select your answer - b. What is the estimated proportion of hotel rooms occupied each year (to 2 decimals)? Current Year Current year Previous Year c. Conduct a hypothesis test. What is the p-value (to 4 decimals)? Use Table 1 from Appendix B. p-value = Using a 0.05 level of significance, what is your conclusion? Previous Year - We - Select your answer that there…arrow_forward
- According to a 2006 survey conducted by the Center for Disease Control and Prevention (CDC), birth rates peak slightly between July and October each year. While a slight numerical increase in birth rates is often observed, this difference is assumed to be statistically non-significant. Thus, we would expect to see an equal number of people born during each month of the year in the United States. The "Birth Data.jasp" contains the birth months for 1380 babies (N = 1380) born during the year 2006 in the United States collected by the CDC. Conduct a Chi-Square Goodness of Fit Test at α = 0.05, to see if the number of babies born each month “fits” with the CDC’s assumptions about the population. Identify the correct value for df. A. 5.72 B. 11 C. 107 D. 0.89arrow_forwardAccording to a 2006 survey conducted by the Center for Disease Control and Prevention (CDC), birth rates peak slightly between July and October each year. While a slight numerical increase in birth rates is often observed, this difference is assumed to be statistically non-significant. Thus, we would expect to see an equal number of people born during each month of the year in the United States. The "Birth Data.jasp" contains the birth months for 1380 babies (N = 1380) born during the year 2006 in the United States collected by the CDC. Conduct a Chi-Square Goodness of Fit Test at α = 0.05, to see if the number of babies born each month “fits” with the CDC’s assumptions about the population. What is the value of X2-crit? A. 5.72 B. 4.72 C. 19.68 D. 21.92arrow_forwardAccording to a 2006 survey conducted by the Center for Disease Control and Prevention (CDC), birth rates peak slightly between July and October each year. While a slight numerical increase in birth rates is often observed, this difference is assumed to be statistically non-significant. Thus, we would expect to see an equal number of people born during each month of the year in the United States. The "Birth Data.jasp" contains the birth months for 1380 babies (N = 1380) born during the year 2006 in the United States collected by the CDC. Conduct a Chi-Square Goodness of Fit Test at α = 0.05, to see if the number of babies born each month “fits” with the CDC’s assumptions about the population. Identify the correct alternative hypothesis A. H0: The number of babies born throughout the year is equal across all 12 months B. HA: The number of babies born in at least one month of the sample is equal to the number of babies born in at least one month of the population C. HA: The…arrow_forward
- According to a 2006 survey conducted by the Center for Disease Control and Prevention (CDC), birth rates peak slightly between July and October each year. While a slight numerical increase in birth rates is often observed, this difference is assumed to be statistically non-significant. Thus, we would expect to see an equal number of people born during each month of the year in the United States. The "Birth Data.jasp" contains the birth months for 1380 babies (N = 1380) born during the year 2006 in the United States collected by the CDC. Conduct a Chi-Square Goodness of Fit Test at α = 0.05, to see if the number of babies born each month “fits” with the CDC’s assumptions about the population. Identify the correct null hypothesis. A. H0: The number of babies born throughout the year is equal across all 12 months B. H0: The number of babies born during the summer months is greater than the number of babies born during the rest of the year C. HA: The number of babies born in…arrow_forwardPART 2 (CLO 2) Test a claim that the mean height of people you know is not equal to 64 inches using the p-value method or the traditional method by completing the following: PERSON WEIGHT HEIGHT (INCHES) Person 1 160 62 Person 2 180 67 Person 3 187 68 Person 4 202 71 Person 5 142 65 Person 6 201 65 Person 7 150 66 Person 8 133 62 Person 9 120 64 State H0 and H1. Find the p-value or critical value(s). Draw a conclusion in the context of the situation.arrow_forwardThe Kyoto Protocol was signed in 1997, and required countries to start reducing their carbon emissions. The protocol became enforceable in February 2005. In 2004, the mean CO2 emission was 4.87 metric tons per capita. Table 7.3.3 contains a random sample of CO2 emissions in 2010 ("CO2 emissions," 2013). Is there enough evidence to show that the mean CO2 emission is lower in 2010 than in 2004? Test at the 1% level. Table #7.3.3: CO2 Emissions (in metric tons per capita) in 2010 1.36 1.42 5.93 5.36 0.06 9.11 7.32 7.93 6.72 0.78 1.80 0.20 2.27 0.28 5.86 3.46 1.46 0.14 2.62 0.79 7.48 0.86 7.84 2.87 2.45 Question 5:)Table #7.3.7 contains pulse rates after running for 1 minute, collected from females who drink alcohol ("Pulse rates before," 2013). The mean pulse rate after running for 1 minute of females who do not drink is 97 beats per minute. Do the data show that the mean pulse rate of females who do drink alcohol is higher than the mean pulse rate of females who do…arrow_forward
- 24. answer part barrow_forward10. Journal Science and Technology published a study on the ammonia levels in the air near an exit ramp of a highway tunnel in the state of Selangor. The data in the table represent daily ammonia concentrations (in unit) on twelve randomly selected days in June 2011. 1.53 | 1.37 | 1.51 | 1.55 | 1.40 | 1.49 1.50 1.45 | 1.42 | 1.48 | 1.47 | 1.41 a) Construct a 99% confidence interval for mean daily ammonia level in the tunnel assuming that the ammonia level follows a normal distribution with variance of 0.25 unit. b) Construct a 99% confidence interval for mean daily ammonia level in the tunnel assuming. that the ammonia level follows a normal distribution. c) Construct a 95% confidence interval for the standard deviation of daily ammonia level in the tunnel.arrow_forwardThis question has part a,b,and c.arrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill
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