1.3 A random set of boys and girls who formed part of a sociology experimentconducted at the University of Cape Town, are observed to respond differently toa specified situation. Their response rates are reflected in Table 1.Table 1: Response ratesResponse Type Females Males(Girls)50%(Boys)Good60%The experimental group of 50 kids, 20 boys and 30 girls aged between 6 and 10years old, was exposed to these specified settings, and they were requested todescribe their responses on a digital survey. A random response selected fromthe 50 kids was bad. Determine whatthe probability was that it was boy?

The two by two contingency table represents two classifications of a set of counts or frequencies.…

Answered: 1.3 A random set of boys and girls who…

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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2. Juvenile free-living ground squirrels utilize responses known as "alarm calls" in response to predators. These calls can alert others to danger. Newly weaned squirrels emerge from the nest at about 25 days of age. Do the squirrels emerge with automatic responses to alarm signals, or are the responses learned? To answer this question, a biologist played recordings of alarm calls for three random samples from populations (by age) of squirrels and observed the squirrels' responses. She reasoned that if the responses were not different for the different age groups, the squirrels must be responding by instinct. On the other hand, if the responses differ with the age of the squirrels the young squirrels must be learning to respond to the alarm calls. Her data for the responses, categorized by age, is presented below: Response to alarm call Enter or Stand up or run to burrow freeze Totals Days since weaning 1-5 21 18 39 6-10 16 24 40 10-15 12 19 Totals 49 49 98 Is there convincing evidence…
1.) Suppose we recorded the following data from an experiment: SUBJECT 1 GENDER M - 2 3 - F M - LIVER WT1 LIVER_WT2 SPLEEN 10.2 7.2 8.9 9.8 8.3 9.3 12.2 11.1 9.1 a.) Use a DATA STEP to input the data. b.) Create a new variable AVERAGE_WT, which is the average of LIVER_WT1 and LIVER_WT2. c.) Use a PROC PRINT step, following the DATA step, to list the contents of the data set you are asked to create in the problem. d.) Copy and paste your PROC PRINT table output as your answer.
Researchers investigate how the presence of cell phones influence the quality of human interaction. Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room. Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment. What statistical test is appropriate?
2. A researcher wants to determine which of three advertisements is most likely to encourage teens not to smoke. To assess the impact of each advertisement, she asks a sample of teenagers to view each ad and to rate the ad's effectiveness on a scale of 1 (not at all effective) to 7 (very effective). One ad used words only (no-cues condition), a second ad used a generic abstract picture (generic-cues condition), and a third showed a picture of a teen smoking and coughing (smoking-related cues condition). Fully test the question (5 steps) and determine the effect size. Participant ABCDEFG No Cues 2 3 1 4 4 5 2 T = 21 SS = 12 Generic Cues 5 5 4 5 3 4 2 T1 = 28 SS=8 Smoking- Related Cue 5 6 5 7 6 7 6 T2 = 42 SS = 4 P G = 91 ΣΧ2 = 451
1. A hospital keeps a record of the number of males and females in different age groups who contract a particular disease. The data are summarized as follows: Age Groups: 10-25 26-40 41-55 56 + Male: 23, 34, 20, 64 Female: 31, 29, 55, 44 a) Are gender and age of contracting the disease independent of one another (a < .05)? b) A researcher believes that people in the 41-55 age group are three times as likely to develop the disease as are those in each of the two younger age groups, while those in the 56 + age group are only twice as likely (relative to those in the two youngest groups). The two youngest age groups are not expected to differ from each other. Do the data support these beliefs (a < .01)? c) It is also believed that, relative to males, the proportion of females in the 56 + age group that develops the disease is significantly different from the proportion of females in the 10-25 age group that develops the disease. Test this belief with a 5.05. Answers 1. a) x2 =…
2. It is known that the student score data in a class is as follows: 9, 8, 6, 7, 7, 8, 5, 3, 6, 7 Describe the data in terms of central tendency!
14. A total of 12 participants were randomly assigned to one of three treatment groups: antidepressant medication ("drug"), weekly psychotherapy ("therapy”), or no treatment ("control"). Depression scores were collected 8 weeks after treatment began. We want to know how effective the depression treatments were (that is, do the mean depression scores differ between groups?). Drug Drug Drug b) Determine what test to use. Drug Therapy Therapy Therapy Therapy Control Control Control Control a) What are the null and alternative hypotheses? 8 9 14 6 12 7 15 8 22 25 18 20 c) Determine alpha, how many tails are there, what are the df and find a critical value.
The manager of a company that assembles and exports a particular type of pumps wants to know if there is a link between the number of hours spent by assembly workers in training and their productivity on the job. A random sample of 7 assembly workers was selected and their performances evaluated. The summary of the obtained data is listed in Table 2. Table 2: Shows the time spend by workers during training and their productivity on jobTraining hours (x) 20 36 20 38 40 33 32Output (y) 40 70 44 56 60 48 62 (i) Construct a scatter plot of the sample data and comment on the relationship between hours of training and output. (ii) Estimate a simple regression line, using the method of least squares, to identify a linear relationship between the hours of training received by assembly workers and their output (i.e. number of units assembled per day). (iii) Interpret, in context, the gradient/slope of the regression line. (iv) Estimated the output at 20 hours training time. (v) Interpret the…
8) The following results are from data that were collected from the various high schools around the county. The dependent variable is % OF STUDENTS GOING TO COLLEGE, and the independent variables are: AVERAGE CLASS SIZE, COMBINED SAT SCORES, SPENDING PER STUDENT, AVERAGE TEACHER SALARY, AND % TAKING THE SAT Since the 3 variables AVERAGE CLASS SIZE, SPENDING PER STUDENT, AND AVERAGE TEACHER SALARY are each not significant at the 10% level of significance individually, in order to test to see if as a group they are significant the 3 variables are excluded and another regression is run. The results are as follows: a) At the 10% level of significance, test whether as a group AVERAGE CLASS SIZE, SPENDING PER STUDENT, AND AVERAGE TEACHER SALARY are significant. Be sure to state the null and alternative hypotheses for this hypothesis test.
6. Analysis of variance has long been used in providing evidence of the effectiveness of pharmaceutical drugs. Such evidence is required before Philippine Food and Drugs Authority (PFDA) will allow a drug to be marketed. In a recent test of the effectiveness of a new sleeping pill, three groups of 25 patients each were given the following treatments. The first group was given the drug, the second group was given the placebo, and the third group was given no treatment at all. The number of minutes it took each person to fall asleep was recorded. The results are as follows: Drug group: 12 17 34 11 5 42 18 27 2 37 50 32 12 27 21 10 4 33 63 22 41 19 28 29 8 Placebo group: 44 32 28 30 22 12 3 12 42 13 27 54 56 32 37 28 22 22 24 9 20 4 13 42 67 No treatment group: 32 33 21 12 15 14 55 67 72 1 44 60 36 38 49 66 89 63 23 6 9 56 28 39 59 Use Analysis of Variance to determine whether the drug is effective. Give differences in average effectiveness, if any exist. Use a = .05.
1. A developmental psychologist would also like to determine how much fine motor skill improves for children from age 3 to age 4 but is worried about practice effects. She takes a random sample of 9 three-year old children and a second sample of 9 four-year olds and measures fine motor skill in each using the same test described above. Her data are provided below. Three Year Olds: 40, 35, 38, 39, 40, 50, 40, 38, 42 Four Year Olds: 35, 36, 39, 29, 35, 34, 33, 34, 35 a. Is there a significant difference in the motor skills from age three to four? Test with an α = 0.01. b. What type of error is possible based on the outcome? c. Calculate and interpret the effect size. d. What is the mean motor skill score for the age three children? What is the mean motor skill score for the age four children?
6) Any basketball fan knows that Shaquille O’Neal, one of the NBA’s most dominant centers of the last twenty years, always had difficulty shooting free throws. Over the course of his career, his overall made free-throw percentage was 53.3%. During one off-season, Shaq had been working with an assistant coach on his free-throw technique. During the next season, a simple random sample showed that Shaq made 26 of 39 free-throw attempts. Test the claim that Shaq has significantly improved his free-throw shooting using a 0.05 significance level. Check the conditions of the Central Limit Theorem for this scenario. Calculate the number of failures.

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