A sample of 50 night-school students' ages is obtained in order to estimate the mean age of night-school students. x = 24.3 years. The population variance is 16.

(b) Find the 95% confidence interval for μ. (Give your answer correct to two decimal places.)

Lower Limit

Upper Limit

(c) Find the 99% confidence interval for μ. (Give your answer correct to two decimal places.)

Lower Limit

Upper Limit

Here are summary statistics for randomly selected weights of newborn​ girls:

nequals=221

x overbar x=28.8

​hg,

s=7.9

hg. Construct a confidence interval estimate of the mean. Use a

99%

confidence level. Are these results very different from the confidence interval

25.0

hg less than<muμless than<31.4

hg with only

12

sample​ values,

x overbarxequals=28.2

​hg, and

sequals=3.6

​hg?

What is the confidence interval for the population mean

muμ​?

nothing

hgless than<muμless than<nothing

hg ​(Round to one decimal place as​ needed.)

Are the results between the two confidence intervals very​ different?

A.

​No, because the confidence interval limits are similar.

B.

​Yes, because the confidence interval limits are not similar.

C.

​No, because each confidence interval contains the mean of the other confidence interval.

D.

​Yes, because one confidence interval does not contain the mean of the other confidence interval.

Following is a contingency table providing a cross-classification of worldwide reported shark attacks during the 1990s, by country and lethality of attack.

1. Find the probability that the attack was Nonfatal
2. Find the probability that Brazil reported
3. Find the probability that Brazil reported the attack was Nonfatal
4. Find the probability that Brazil reported or the attack was Nonfatal
5. Find the probability that Brazil reported given that the attack was Nonfatal
6. Find the probability that the attach was Nonfatal given that Brazil reported
7. Construct a Relative Frequency Contingency Table, determine parts (i-vi) again
8. Verify your answers obtained from contingency table and relative frequency contingency table

Is the national crime rate really going down? Some sociologists say yes! They say that the reason for the decline in crime rates in the 1980s and 1990s is demographics. It seems that the population is aging, and older people commit fewer crimes. According to the FBI and the Justice Department, 70% of all arrests are of males aged 15 to 34 years†. Suppose you are a sociologist in Rock Springs, Wyoming, and a random sample of police files showed that of 37 arrests last month, 24 were of males aged 15 to 34 years. Use a 1% level of significance to test the claim that the population proportion of such arrests in Rock Springs is different from 70%.

What is the value of the sample test statistic? (Round your answer to two decimal places.)

Find the P-value of the test statistic. (Round your answer to four decimal places.)

College Graduation Rates. Data from the College Results Online website compared the 2011 graduation rate and school size for 92 similar-sized public universities and colleges in the United States. Statistical software was used to create the linear regression model using size as the explanatory variable and graduation rate as the response variable. Summary output from the software and the scatter plot are shown below. Round all calculated results to four decimal places.

Residual standard error: 13.1 on 90 degrees of freedom
Multiple R-squared: 0.0504,Adjusted R-squared: 0.0398
F-statistic: 4.77 on 1 and 90 DF, p-value: 0.031

1. Write the equation for the regression line for predicting graduation rate from the size of the school.

Grad Rate =  +  (Size)

2.Complete the following sentence:

% of the variation in  ? Graduation rate Size School  can be explained by the linear relationship to  ? Graduation rate Size School .

Do the data provide strong evidence (?α = 0.05) that the size of the school is associated with the graduation rate? Conduct a t-test using the information given in the R output and the hypotheses

?0:?1=0H0:β1=0 vs. ??:?1≠0HA:β1≠0

Use ?α = 0.05.

3. Test statistic =

4. Degrees of freedom =

5. P-value =

6. Based on the results of this hypothesis test, there  ? is is not  a significant linear relationship between the explanatory and response variables.

7. Calculate a 95% confidence interval for the slope, ?1β1. (  ,  )

Developmental Psychology

Reflect on the following case:

1. What do you see as the major problems Raul is exhibiting? (If you had to take a guess at a possible diagnosis, what would it be? Anything?)

2. Identify all the risk factors and identify all the protective factors affecting Raul's development.

3. What strengths or resources in Raul and his famlly would you emphasize as a way to improve his chances of a good developmental outcome?

Case Study: Raul Salazar -- 10-year-old boy

Raul Salazar, a 10-year-old boy, has just started the fourth grade. He was referred to the school's multidisciplinary team because of reports of difficulties in school and concerns about his home situation. Teachers are questioning whether he has a learning disability. They are also asking the team to determine whether he is an appropriate candidate for medications. He often does not follow instructions well. However, his current teacher is "surprised by his vocabulary." It is "much better than many of the other Puerto Rican kids in his class." However, his performance in school has steadily deteriorated. He especially has problems with reading and mathematics and on occasion comes to school with dirty clothing and falls asleep in class.

His performance in the third grade was average, but his records indicate that the teachers at the other school considered him to be a very anxious child. These teachers reported that Raul constantly moved in his seat and had problems with writing but did well in other fine-motor tasks.

Another fact that stands out in his school history is that his performance was better when he was attending a smaller parochial school for Grades 1 and 2.

Raul has two other siblings. He has an older brother who is 13, and a younger sister who is 9 years old. Raul's father works for the city of New York as a painter, and is mother is a teaching assistant. She completed two years of college but had to leave her education because she got pregnant with their oldest son.

Raul's mother's family moved to the mainland when she was eight years of age. Her father was a teacher and they were not very pleased when she "had to marry" Raul's father. Raul's father's family came from a poor rural area on the island. His own father had a history of alcoholism and left the family when Mr. Salazar was very young.

Mrs. Salazar reported to the social worker that she had serious problems with her nerves throughout her life and that they become worse whenever she is pregnant. Otherwise she felt her pregnancy with Raul had been normal. However, school staff learned that there had been some fear that she might lose Raul during the pregnancy, and this is why she was prescribed bed rest during the last trimester.

Mrs. Salazar's third child, her daughter Maria, was born prematurely, but Mrs. Salazar did not have any problems with her first pregnancy. She told the social worker that her daughter's premature status really hit the family hard because Maria required so much care when she finally came home.

Unfortunately, Mr. Salazar was released from his job shortly after Maria's birth, and he was out of work for 9 months. The mother reports this was possibly the most stressful period in her life. When Maria was about four months old, Mrs. Salazar had a seizure. Mrs. Salazar's doctor considered placing Mrs. Salazar on medication after she had that seizure; however, testing did not reveal any evidence of the presence of a seizure disorder. She reports a history of fainting and other seizure-like experiences when she was a teenager.

Mrs. Salazar says that she has always had problems with her nerves and has been very sickly throughout her life. She also told the social worker that "she was always the weakest one in her family." When Raul was about eighteen months old, Mrs. Salazar's closest brother was killed in a car accident. She reports not being able to get out of bed for weeks following the news of his death. Raul's medical records indicate that it was approximately around this time that he started banging his head in order to fall asleep.

This habit continued until he was about six years of age. He also developed some other habits that persist to this date. He still bites his fingernails very often. Raul's history also reveals that he was extremely frightened of the dark as a child and has an extreme startled response for which he is often teased by his brother and father.

The family moved to New York City one year ago, in order for Raul's father to take a job as a city-employed painter. The move is why Raul had to switch schools.

Raul's father is a strict disciplinarian. He told workers that he often loses his temper and yells at the children, but he says that he has never physically abused them. He reported to the social worker that he cannot tolerate the kids being noisy. When he comes home from his new job, his wife is often in bed, and things are a mess. Mr. Salazar is under lots of pressure at work. His supervisor does not like Puerto Ricans and gives him all the worst job assignments. The family no longer lives near other family members because they moved for Mr. Salazar to get his city job. Mr. Salazar told the social worker that the family is willing to pay for any services that will help his son do well in school.

Which of the following is not an example of structural unemployment?

Select the correct answer below:

Morgan never finished high school and has trouble finding work that she is qualified for. Companies in her area have declined to hire her.

Will has been offered a job on the other side of the country. Before he can start working, he expects to need around a month to sell his house and move to the new location.

Molly completed an advanced degree in a highly specific engineering discipline. Since graduating, she has not been able to find a job that matches her expertise.

Steven lost his manufacturing job when the company he worked for shut down. There are no other opportunities for him in the same industry and he lacks the skills to pursue other types of work.

2. An important debate among macroeconomists concerned the interest rate elasticity of money demand. Monetarists believed that money demand was very sensitive to interest rate changes, while Keynesians believed that money demand was insensitive to interest rate changes.
   1. Show how different assumptions about the interest rate elasticity of money demand affect the slope of the LM curve. To do this, derive the LM curve for both Keynesians and monetarists on the same set of diagrams so we can visualize the differences.
   2. Given what you find in (a), which school of thought believed that a tax cut would have a stronger impact on aggregate output? Illustrate by drawing a new IS-LM diagram with both a monetarist and Keynesian LM curve drawn on it. Explain your logic in detail.