In Exercises 5–20, assume that the two samples are independent simple random samples selected from
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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- II. Conduct a hypothesis test A research center claims that less than 50% of senior high school students in public schools in the Philippines have accessed the Internet using cellular phones. In a random sample of 100 SHS students, 39% say they have accessed the Internet using cellular phones. At = 0.01, is there enough evidence to support the researcher's claim?arrow_forwardwhich statement is true and false?arrow_forward(b) Figure Q1(b) shows the data from the survey conducted among teenagers who drive a car on the rural road and their involvement with traffic accidents. Based on the information given: Provide your calculation of the total numbers of teenagers who drive a car on the road. i. ii. Based on your understanding what is the probability of teenagers getting involved in accidents during both day and night times? iii. Interpret the probability of teenagers who were not getting involved in accidents during day time.arrow_forward
- A random sample of n1 = 10 regions in New England gave the following violent crime rates (per million population). x1: New England Crime Rate 3.2 3.1 4.0 3.2 3.3 4.1 1.8 4.8 2.9 3.1 Another random sample of n2 = 12 regions in the Rocky Mountain states gave the following violent crime rates (per million population). x2: Rocky Mountain Crime Rate 3.7 4.1 4.5 5.1 3.3 4.8 3.5 2.4 3.1 3.5 5.2 2.8 Assume that the crime rate distribution is approximately normal in both regions. Note: If a two-sample t-test is appropriate, for degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more "conservative" answer.Use a calculator to calculate x1, s1, x2, and s2. (Round your answers to two decimal places.) x1 = s1 = x2 = s2 = (a) Do the data indicate that the violent crime rate in the Rocky Mountain…arrow_forward3. A study in Men's Health magazine stated that 14% of men said they used exercise to reduce stress. Use a = 0.10. A random sample of 100 men was selected and 10 said they used exercise. Does the sample support the claim made by the magazine?arrow_forwardAn automobile dealer conducted a test to determine if the time in minutes needed to complete a minor engine tune-up depends on whether a computerized engine analyzer or an electronic analyzer is used. Because tune-up time varies among compact, intermediate, and full-sized cars, the three types of cars were used as blocks in the experiment. The data obtained follow. Analyzer Computerized Electronic Car Compact 51 42 Intermediate 55 43 Full-sized 62 47 Use ? = 0.05 to test for any significant differences. State the null and alternative hypotheses. H0: ?Computerized ≠ ?ElectronicHa: ?Computerized = ?ElectronicH0: ?Computerized = ?Electronic = ?Compact = ?Intermediate = ?Full-sizedHa: Not all the population means are equal. H0: ?Computerized = ?ElectronicHa: ?Computerized ≠ ?ElectronicH0: ?Compact ≠ ?Intermediate ≠ ?Full-sizedHa: ?Compact = ?Intermediate = ?Full-sizedH0: ?Compact = ?Intermediate = ?Full-sizedHa: ?Compact ≠ ?Intermediate ≠ ?Full-sized Find the value of…arrow_forward
- A certain virus affects 0.7% of the population. A test used to detect the virus in a person is positive 87% of the time if the person has the virus (true positive) and 14% of the time if the person does not have the virus (false positive). Fill out the remainder of the following table and use it to answer the two questions below based on a total sample of 100,000 people. Virus No Virus TotalPositive Test Negative Test Total 100,000a) Find the probability that a person has the virus given that they have tested positive. Round your answer to the nearest hundredth of a percent and do not include a percent sign. % b) Find the probability that a person does not have the virus given that they test negative. Round your answer to the nearest hundredth of a percent and do not include a percent sign. %arrow_forwardA statistician wants to determine if there is a difference in the fuel efficiency of cars between model years. To do this, he selects random makes and models of cars and compares the fuel efficiency in miles per gallon of the current model year and the previous model year. Suppose that data were collected for a random sample of 9 cars, where each difference is calculated by subtracting the fuel efficiency in miles per gallon of the previous model year from the fuel efficiency in miles per gallon of the current model year. Assume that the fuel efficiencies are normally distributed. What type of test is this hypothesis test? A. This is a two-tailed test because the alternative hypothesis is Ha:μd≠0. B. This is a right-tailed test because the alternative hypothesis is Ha:μd>0. C. This is a right-tailed test because the alternative hypothesis is Ha:μd<0. D. This is a left-tailed test because the alternative hypothesis is Ha:μd<0. E. This is a left-tailed…arrow_forwardplease answer part barrow_forward
- A random sample of n1 = 10 regions in New England gave the following violent crime rates (per million population). x1: New England Crime Rate 3.3 3.9 4.2 4.1 3.3 4.1 1.8 4.8 2.9 3.1 Another random sample of n2 = 12 regions in the Rocky Mountain states gave the following violent crime rates (per million population). x2: Rocky Mountain Crime Rate 3.7 4.1 4.7 5.5 3.3 4.8 3.5 2.4 3.1 3.5 5.2 2.8 Assume that the crime rate distribution is approximately normal in both regions. Do the data indicate that the violent crime rate in the Rocky Mountain region is higher than in New England? Use ? = 0.01. Solve the problem using both the traditional method and the P-value method. (Test the difference ?1 − ?2. Round the test statistic and critical value to three decimal places.) test statistic critical value Find (or estimate) the P-value. P-value > 0.250 0.125 < P-value < 0.250 0.050 < P-value < 0.125 0.025 < P-value < 0.050 0.005 <…arrow_forwardA random sample of n1 = 10 regions in New England gave the following violent crime rates (per million population). x1: New England Crime Rate 3.3 3.9 4.2 4.1 3.3 4.1 1.8 4.8 2.9 3.1 Another random sample of n2 = 12 regions in the Rocky Mountain states gave the following violent crime rates (per million population). x2: Rocky Mountain Crime Rate 3.7 4.1 4.7 5.5 3.3 4.8 3.5 2.4 3.1 3.5 5.2 2.8 Assume that the crime rate distribution is approximately normal in both regions. Do the data indicate that the violent crime rate in the Rocky Mountain region is higher than in New England? Use ? = 0.01. Solve the problem using both the traditional method and the P-value method. (Test the difference ?1 − ?2. Round the test statistic and critical value to three decimal places.) test statistic critical value Find (or estimate) the P-value. P-value > 0.2500.125 < P-value < 0.250 0.050 < P-value < 0.1250.025 < P-value < 0.0500.005 <…arrow_forwardA random sample of n1 = 10 regions in New England gave the following violent crime rates (per million population). x1: New England Crime Rate 3.3 3.9 4.2 4.1 3.3 4.1 1.8 4.8 2.9 3.1 Another random sample of n2 = 12 regions in the Rocky Mountain states gave the following violent crime rates (per million population). x2: Rocky Mountain Crime Rate 3.7 4.1 4.7 5.5 3.3 4.8 3.5 2.4 3.1 3.5 5.2 2.8 Assume that the crime rate distribution is approximately normal in both regions. Do the data indicate that the violent crime rate in the Rocky Mountain region is higher than in New England? Use α = 0.01. Solve the problem using both the traditional method and the P-value method. (Test the difference μ1 − μ2. Round the test statistic and critical value to three decimal places.) test statistic critical valuearrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill