9. Children (approximately 11 years old) with cochlear implants (CI) and children with typical hearing (TH) were asked to listen to speech with a background of noise under different conditions in a classroom setting. The different conditions were the number of sound-absorbing acoustic panels hung on the walls in the classroom. This affected the reverberation time (RT). With more panels, there was less reverberation (0.3s). With fewer panels, there was more reverberation (0.9s). The signal-to-noise ratio was measured in decibels (dBA). The higher the number, the speech was louder than the noise. The lower the number (<0) the noise was louder than the speech.

a. Did children with cochlear implants score higher on speech perception at higher signal-to-noise ratios than children with typical hearing? Give data in support of your answer. [2]

b. You are in charge of classroom design for a school with mixed CI and TH children. What do you recommend? Give reasons with data. [2]

A random sample of 80 eighth grade​ students' scores on a national mathematics assessment test paper has a mean score of 269. This test result prompts a state school administrator to declare that the mean score for the​ state's eighth graders on this paper is more than 260 Assume that the population standard deviation is 31. At alphaαequals=0.06 is there enough evidence to support the​ administrator's claim? Complete parts​ (a) through​ (e).

​(a) Write the claim mathematically and identify Upper H 0H0 and Upper H Subscript aHa.

​(b) Find the standardized test statistic​ z, and its corresponding area.

​(c) Find the​ P-value.

​(d) Decide whether to reject or fail to reject the null hypothesis.

​(e) Interpret your decision in the context of the original claim.

At the 6​% significance​ level, there (Blank) enough evidence to Blank the​ administrator's claim that the mean score for the​ state's eighth graders on the paper is more than 260.

In the field of economics, there are few men who cast a bigger shadow than Milton Friedman. One of his (among many) central ideas is the Friedman Doctrine which states that corporations have no social responsibility (as long as they play by the rules) beyond profit maximization. This approach is often criticized by those that believe corporations should be good "corporate citizens".  

You will research the life and career of Milton Friedman providing an overview of his life and main economic theories paying particular close attention to the finer points of the Friedman doctrine. The paper should focus on these main ideas and use at least 3 outside resources:

1. What was Friedman's educational background?

2. What school of thought is he associated with?

3. What are some concepts attributed to him (Friedman doctrine must be explained in detail)?

4. What is your personal position on the responsibility of corporations to society?

5. Can a company be socially responsible and maximize profits (give examples!)?

Scope creep refers to the tiny, incremental change or addition of requirements to an already-defined project so that, for example, a project that began by trying to produce a single ham sandwich ended up trying to produce a three-course meal for 20 people.

For this discussion, describe a time when scope creep happened on a project in which you were involved. The project you describe may be from work (such as being affected by an IT upgrade project), school (such as participating in a team assignment), or personal life (such as planning a wedding).

• Who was responsible for adding requirements?
• Who was responsible for accepting them?
• Were the additional requirements introduced early in the project process, or late?
• What were the outcomes? That is, was the expanded scope implemented, or not?
• Did the project come in over budget? Was it delayed? Was it cancelled?

If you have never been involved in any type of project in which scope creep occurred, research specific causes of project scope creep and share at least two causes

The National Center for Education Statistics found that in 2015, 41% of students nationwide reported that their mothers had graduated from college. A superintendent randomly sampled 356 students from her local school district and found that 43% of them had mothers that graduated from college. Does her sample give evidence of a higher education level among mothers in her district? Use a significance level of ? = 0.05.

a) State the hypotheses in symbols.   

b) Run the test and report the test statistic and p-value. Be sure to write out what you entered in your calculator.

c) Write a full conclusion for this test in the context of the problem (see #2b for format).   

d) Find a 90% confidence interval for the proportion of students in the superintendent’s district that have mothers who graduated from college. Be sure to write out what you entered in your calculator.

e) Does this confidence interval support your conclusion in part (c)? Explain.

Given the following research topic, answer the question below: Are there differences in university GPA and persistence rates between who enrolled in first-year seminars compared to those who did not enroll in first-year seminars?

a. What is the dependent variable(s)?

b. Are there any other dependent variables that might be of interest in this study?

c. What is the independent variable? Identify levels of the variable.

d. Why is this an example of ex post facto research?

e. Consider the extraneous variable high school (HS) GPA. Describe how you could control this extraneous variable through ANCOVA.

f. Consider the extraneous variable academic major. Describe how you could control this extraneous variable through homogeneous grouping.

g. Consider the extraneous variable campus living arrangement. Describe how you could control this extraneous variable through homogeneous grouping.

h. Suggest one additional extraneous variable and one way to control it.

1. A researcher wishes to examine the relationship between wage earned and educational level of workers. For a sample of 4000 workers she has data on hourly earnings (measured in SAR), age of the worker (in years), worker’s gender, years of experience, number of years with the present employer, size of the firm in which the worker is employed, and highest educational qualification (with 4 classifications: no qualification, secondary school certificate, bachelor degree or PhD)

1. Explain how you would set up a model to address the researcher’s key interest.
2. Based on your model, how would you estimate the predicted impact on wages of holding a PhD compared to having a bachelor’s degree.
3. If the researcher uses ln(wage) as the dependent variable, how would the estimated coefficients be interpreted?
4. What general advice would you give the researcher in relation to her work – eg. what econometric issues should she be aware of in conducting this research and interpreting the results?

A researcher wishes to examine the relationship between wage earned and educational level of workers. For a sample of 4000 workers she has data on hourly earnings (measured in SAR), age of the worker (in years), worker’s gender, years of experience, number of years with the present employer, size of the firm in which the worker is employed, and highest educational qualification (with 4 classifications: no qualification, secondary school certificate, bachelor degree or PhD)

1. Explain how you would set up a model to address the researcher’s key interest.
2. Based on your model, how would you estimate the predicted impact on wages of holding a PhD compared to having a bachelor’s degree.
3. If the researcher uses ln(wage) as the dependent variable, how would the estimated coefficients be interpreted?
4. What general advice would you give the researcher in relation to her work – eg. what econometric issues should she be aware of in conducting this research and interpreting the results?