A ["prospective", OR "retrospective"] cohort study is carried out to investigate the association between occupational arsenic inhalation and neurological exposure and neurological effects among workers in a copper smelter. For the sake of simplicity, let’s assume there are two possible exposure categories: high and low (for example, those working in the smelting process and those working in administration). The exposure was carefully assessed by review of company records which reflected very good exposure monitoring (both air sampling and urine testing). The outcome was based on self-reported information from an interview that asked: “Have you had tingling in your fingers in the last month that lasted more than 30 minutes?” Those that said “yes” were classified as “diseased”, and those that said “no” were the “non-diseased” group. In order to avoid ["information bias", OR "selection bias"]   bias, the company encouraged everyone to participate by telling their workers that they were a concerned employer and wanted to know if there were adverse neurological effects from the potential arsenic exposure in some of the work areas.

The following is the resulting 2 x 2 table:

Problem 8: The Framingham Heart Study was a longitudinal cohort study of 5000+ men and women. One outcome of interest was fasting glucose levels. Glucose levels were categorized into three different categories:

Glucose Levels

     -Diabetes (glucose >126),

    -Impaired Fasting Glucose (glucose 100-125),

    -Normal Glucose

Several possible risk factors were also recorded:

Risk Factors

     -Sex

     -Age

     -BMI (normal weight, overweight, obese)

     -Genetics

To determine if each possible risk factor is related to glucose levels,researchers need to use an appropriate hypothesis test.

Test Choices

1. ANOVA

2. Chi-Square GOF

3. Chi-Square test for independence

4. Test for equality of means

5. Test for equality of proportions

6. Other

a. What test would be used to assess whether the different sexes(male and female) have the same proportions of the different glucose levels?

b. What test would be used to assess whether the different glucose levels have the same mean age?

c. What test would be used to assess whether the different categories of BMI have the same proportions of the different glucose levels?

Researchers conducted a cohort study of the association between air pollution and asthma. The

rate ratio was 8.0, when comparing those exposed to high levels of air pollution with those

exposed to low levels of air pollution. Which of the following issues should the researchers

consider when making their study conclusions and when thinking about causality? Choose all

that apply and explain your choice.

a) The rate ratio of 8.0 indicates a strong association, which lends support for causality

b) Strong confounding may actually be causing the strong association seen

c) Other studies of the same exposure—health outcome association reported rate ratios in the

range of 1.5-3.0, less than the rate ratio of 8.0 seen in this study

d) The temporal sequence of the exposure and outcome should be known in order to draw

accurate conclusion.

Snapchat is interested in targeting a particular audience group with a new product(Spectacles)and needs to know about the average time a first-year college student spends on Snapchateach day. This way, they can decide whether or not it would be worthwhile to advertise Spectacles to students. Unfortunately, the Snapchatreport does not include specific information about first-year college students, so they don't have u for this population. They hire Serena to find more information.
She does some research online and finds that Website A claims that first-year college students spend on average 4 hours on Snapchatper day and Website B claims that first-year college students spend on average 3 hours on Snapchatper day. Since both sites made different claims, Serena decides to survey first-year students at De Anza to create a confidence interval to decide if the claims are reasonable. The following is a list of 30 responses (in hours):

1. Input the 30 observations into the list 1L of your calculator and use 1-Var-Stats to determine the sample mean X and the sample standard deviation .sRound your answers to 4 decimal places. Again, assume X is approximately normal.
X=_____________ s= ________________
2. Explain in one sentence why the t distribution must be used to create a confidence interval in this situation.
3. Using the information from problems 2 and 3, construct a 95% confidence interval for the population mean the number of hours spent on Snapchatby first-year college students. Round your answer to 4 decimal places. Show all of your work and interpret the confidence interval.
4. Are the claims made by Website A and Website B reasonable or unreasonable? Make your decision based on your 95% confidence interval from problem 4 and explain.
A. Website A’s claim of u=4 hours is reasonable/unreasonable(circle one) because...
B. Website B’s claim of u=3 hours is reasonable/unreasonable(circle one) because...

A university wants to determine if students from different majors are equally likely to be cited for academic dishonesty. They average instances of documented cheating across 10 years for three different academic majors and find the following results: Business Administration (M = 5.1; N = 10), Fine Art (M = 1.9; N = 10), and Nursing (M = 3.2; N = 10). They also calculated the between-group and within-group sum of squares (SS_B = 301.6; SS_W =1343.8). Use a one-way ANOVA (where α = .01) to determine if there are significant differences in cheating rates by major.

1. Identify the alternative hypothesis (F tests are always nondirectional)
2. List your degrees of freedom (within)
3. List your degrees of freedom (between)
4. List your mean squares between groups
5. List your mean squares within groups
6. List your F test statistic
7. List your critical F value(s)
8. Are there statistically significant differences in cheating between majors? (Yes/No)
9. Calculate partial eta-squared (η²) for the effect of major on cheating rates (list as decimal, 0.xx)
10. Calculate Tukey’s HSD
11. Use Tukey’s HSD to determine if the difference in cheating rates between Business Administration majors and Fine Art    majors is statistically significant (Yes/No)

Suppose GDP equals $17 trillion, consumption equals $12.2 trillion, the government spends $3.5 trillion and has a budget deficit of $1.1 trillion.

Calculate public saving, taxes, private saving, national saving, and investment.

Now, assume that the government pursues its goal of updating the physical infrastructure of the economy (e.g. fixing roads, bridges, etc.). They decide to spend an additional $4 trillion on this endeavor (beyond their current spending). Use this new information to recalculate the totals from above for public saving, taxes, private saving, national saving, and investment (assuming GDP stays the same).

Suppose that government spending makes private firms more productive; for example, government spending on roads and bridges lowers the cost of transportation. This means that there are now two effects of government spending, the first being the effects discussed in this chapter of an increase in G and the second being similar to the effects of an increase in the nation’s capital stock K.

(a) Show that an increase in government spending that is productive in this fashion could increase welfare for the representative consumer.

(b) Show that the equilibrium effects on consumption and hours worked for an increase in government spending of this type are ambiguous but that output increases. You must consider income and substitution effects to show this.

Explain does why:

• On the basis of qual workability the surface characteristics of aggregate have a limited impact on the ultimate strength of concrete.

• the surface characteristics of aggregate have a clear impact on ultimate strength of concrete on the basis of qual water content.

• The cylinder strength is higher than that of cube's.

• The aspect ratio of concrete cylinders has no impact on compressive strength obtained in compression testing machine with brush platens.

• Concrete bridges should not be subjected to stress levels higher than 0.55 of ultimate strengths.

• the maximum aggregate size of aggregate have two opposing effects on concrete strength.

1.Which of the following statements is NOT an explanation for how oxygen is released from oxy-hemoglobin.

A. Carbon dioxide has a stronger affinity than oxygen to heme and displaces oxygen in tissues.

B. The formation of carbonic acid lowers the oxygen affinity of hemoglobin in tissues.

C. The structure of deoxyhemoglobin is stabilized by the interaction with BPG.

D. Salt bridges are formed with N-terminal carbamates in deoxyhemoglobin.

E. Salt bridges are formed between acidic and basic side chains of His146 and Asp94, respectively in deoxyhemoglobin

2. Which of the following description of hemoglobin S (HbS) forming fibrous aggregates is FALSE?

A. Valine at position 6 of the β chains forms hydrophobic interaction with other HbS.

B. Formation of aggregates occurs more severely in homozygotes, i.e. both alleles carrying the mutation.

C. The aggregates distort the shape of the red blood cells.

D. The formation of aggregates occurs only in the deoxygenated form of HbS.

E. More aggregates are formed in the lungs.

3. Predict the possible outcome if HbS is stripped of BPG?

A. More tendency of HbS to form aggregates.

B. Less tendency of HbS to form aggregates.

C. No effect on HbS aggregation.

D. HbS form aggregates more rapidly.

E. The sickled cells clog blood capillaries more severely.

4. What would be the change of oxygen dissociation curve of the patient with sickle cell anemia, compared to that of a normal person?

A. Left shift

B. Right shift

C. Up shift

D. No change

E. Becomes hyperbolic

Question 2011 pts

What information do bridges use to determine whether to forward traffic?

Group of answer choices

MAC addresses

IP addresses

traffic conditions at the time

nothing because bridges forward all traffic

Question 2021 pts

A technician is at a small facility that has five computers connected to a central switch and accessing a single server for file and print sharing. One computer becomes unable to connect to the network, while the other four are still connecting properly. Which of the following could be causing the computer to not connect to the network?

Group of answer choices

The server has failed.

The computer's OS needs to be updated.

The switch has failed.

The NIC has failed

Question 2031 pts

Which of the following represents a layer-3 address?

Group of answer choices

www.gleneclarke.com

00-02-3F-6B-25-13

192.168.3.200

COMPUTER1

Question 2041 pts

Which of the following provides the longest cable run distance?

Group of answer choices

single-mode fiber

category 3 UTP

multi-mode fiber

Coax

Question 2051 pts

Which of the following best describes Logical Link Control (LLC)?

Group of answer choices

It is a Layer 1 protocol

It remembers the NICs MAC address

It is a sublayer of the Data Link layer

It controls open network sessions

Question 2061 pts

Routers function at which layer of the OSI model?

Group of answer choices

Physical

Network

Data Link

Transport