10.12 Traffic sign maintenance. Refer to the Journal ofTransportation Engineering (June 2013) study of trafficalulNCDOT sign maintenance, Exercise 8.54 (p. 465). Recall that civilengineers estimated the proportion of traffic signs main-tained by the North Carolina Department of Transportation(NCDOT) that fail minimum retroreflectivity requirements.The researchers were also interested in the proportions ofNCDOT signs with background colors white (regulatorysigns), yellow (warning/caution), red (stop/yield/wrong way),and green (guide/information). In a random sample of 1,000road signs maintained by the NCDOT, 373 were white,447 were yellow, 88 were green, and 92 were red. Supposethat NCDOT stores new signs in a warehouse for use asreplacement signs; of these, 35% are white, 45% are yellow,10% are green, and 10% are red. Does the distribution ofbackground colors for all road signs maintained by NCDOTmatch the color distribution of signs in the warehouse? Testusing a

10.12. A sample of 1,000 road signs maintained by the NCDOT is considered. The count and new sins…

Answered: Traffic sign maintenance. Refer to the…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A group of disabled women ages 65 and older were followed for several years. It was found that those who had a vitamin B12 deficiency were twice as likely to suffer from severe depressions than those who did not.a. Describe the type of study being performed.b. Describe the explanatory variable(s) and response variable(s).
This obstetrician also wanted to determine the impact that three experimental diets had on the birth weights of pregnant mothers. She was also interested if age had an impact on birth weights. She randomly selected 27 pregnant mothers in the first trimester of whom 9 were 20 to 29 years old, 9 were 30 to 39 years old, and 9 were 40 or older. For each age group, she randomly assigned the mothers to one of three diets. After delivery, she measured the birth weight (in grams) of the babies and obtained the data a) What is the blocking variable?
Several methods of estimating the number of seeds in soil samples have been developed by ecologists. An article gave the accompanying data on the number of seeds detected by the direct method and by the stratified method for 27 soil specimens. Specimen Direct Stratified 1 21 7 2 34 38 3 0 7 4 60 58 5 20 54 6 61 61 7 40 27 8 7 7 9 14 7 10 94 100 11 1 0 12 67 58 13 78 67 14 21 54 Specimen Direct Stratified 15 34 27 16 0 0 17 38 38 18 18 14 19 94 94 20 1 14 21 40 47 22 21 21 23 0 0 24 7 14 25 14 40 26 18 14 27 40 78 Do the data provide sufficient evidence to conclude that the mean number of seeds detected differs for the two methods? Test the relevant hypotheses using ? = 0.05. (Use ?direct − ?stratified.) Find the test statistic. (Round your answer to two decimal places.) t = Find the df. (Round your answer down to the nearest whole number.) df = Use technology to find the P-value. (Round your answer to four…
Computer-mediated communication (CMC) is a form of interaction that heavily involves technology (e.g., instant messaging, email). A study was conducted to compare relational intimacy in people interacting via CMC to people meeting face-to-face (FTF). Participants were 48 undergraduate students, of which half were randomly assigned to the CMC group and half assigned to the FTF group. The variable of interest, relational intimacy score, was measured (on a 7-point scale) for each participant after each of three different meeting sessions. Summary statistics for the first meeting session are given here. The researchers hypothesized that, after the first meeting, the mean relational intimacy score for participants in the CMC group would be lower than the mean relational intimacy score for participants in the FTF group. Test the researchers’ hypothesis using α = .10. CMC FTF Number…
Which of these experimental designs has the most statistical power (is more likely to show a true difference between 2 treatment conditions)? A. Between-Subjects B. Descriptive Study C. Correlational Study D. Within-Subjects
I want to assess the effects of diet (control diet, high-sugar diet, high-fat diet) and exercise (no voluntary running wheel, voluntary running wheel) on time spent in a target quadrant (more time indicates better memory). I record the percent time spent in a target quadrant for 30 mice and obtain the following data: Control Diet High-sugar Diet High-fat diet No running wheel 15, 28, 29, 30, 25 24, 20, 30, 32, 20 19, 23, 22, 23, 25 Running wheel 30, 34, 35, 44, 32 21, 22, 28, 26, 29 30, 32, 28, 19, 26 What type of factorial design is this? (ex: # x #) ______________ What is the critical F value you’ll be making a decision based on (assume alpha = .05)? Diet: ____ Exercise: _____ Interaction: ______
A study was done to determine if food insecurity/hunger impacts psychological distress (this is fake data to make it simple, but it is based off of a 2020 study that examined the associations between food insecurity and psychological distress among older people in Ghana). Participants were broken into three groups based on their responses: no food insecurity, moderate food insecurity, and severe food insecurity. Psychological distress was measured on the Kessler Psychological Distress Scale (K10), where scores range from 0 to 50. Enter data and test to determine if there is a significant difference between the 3 groups in psychological distress Food insecurity: Psychological distress scores (higher = more distress) No food insecurity 5 6 8 10 5 4 14 9 Moderate food insecurity 16 14 9 7 14 8 16 17 Severe food insecurity…
The article “Well-Fed Crickets Bowl Maidens Over” (Nature Science Update, February 11, 1999) reported that female field crickets are attracted to males with high chirp rates and hypothesized that chirp rate is related to nutritional status. The usual chirp rate for male field crickets was reported to vary around a mean of 60 chirps per second. To investigate whether the chirp rate was related to nutritional status, investigators fed 22 male crickets a high protein diet for 8 days, after which chirp rate was measured. Let: The parameter μμ be the mean chirp rateof male crickets on a high protein diet for 8 days. Given: The mean chirp rate for the random sample of crickets on the high protein diet was reported to be 65.32 chirps per second with a standard deviation of 12. Research Question: Is there convincing evidence that the mean chirp rate for crickets on a high protein diet implies an advantage in attracting the ladies? It is known that the researchers did not want to…
Researchers studied a group of 30 “self-designated worriers” (i.e. individuals who reported spending at least 10% of the day worrying) and who were over the age of 70 (mean age of 78.1). The researcher randomly assigned the worriers into three groups. For the next four weeks, each group would experience a different approach to handling worry. One group engaged in a worry-focus discussion group. The second group members enjoyed individual therapy. The third group went for daily walks in the park. Data was collected, analyzed, and interpreted. Write a valid one sentence hypothesis statement using proper form of the above research design.
The National Highway traffic Safety Administration requires each U.S. state to carry out an observational study to assess the level of seat belt use in the state. One report summarized data from a study done in a certain state. The proportions in the accompanying table are based on observations of over 25,000 drivers and passengers. Male Female Uses Seatbelt Does Not Use Seat Belt 0.42 0.455 0.08 0.045 Assume that these proportions are representative of adults in this state and that an adult from this state is selected at random. (a) What is the probability that the selected adult does not use a seat belt given that the selected individual is female? (b) What is the probability that the selected individual is female given that the selected individual does not use a seat belt? (c) Are the probabilities from parts (a) and (b) equal? Write a couple of sentences explaining why or why not. They --Select--- ✓ equal. Part (a) is the proportion of [---Select--- ---Select--- and part (b) is the…

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