2-2.  In the 1950’s Matthew Meselson and Franklin Stahl did an experiment in which they took bacteria that had grown for many generations in medium containing the stable nitrogen isotope 15N, and transferred them into medium containing only the 14N isotope of nitrogen.  They purified DNA from these bacteria at time zero (before transfer to 14N) and after 1 and 2 rounds of DNA replication in 14N medium.

1. When they analyzed the density of DNA molecules at time zero (before bacteria had been in the 14N medium), what did they observe?

2. When they analyzed the density of DNA molecules after one round of DNA replication, what did they observe?

3. When they analyzed the density of DNA molecules after two rounds of DNA replication, what did they observe?

4. What was the major conclusion from the Meselson-Stahl experiment?

An article in Solid State Technology, "Orthogonal design for process optimization and its application to plasma etching" by G.Z.Yin and D.W.
Jillie (May, 1987) describes an experiment to determine the effect of the
C2F6 flow rate on the uniformity of the etch on a silicon wafer used in
integrated circuit manufacturing. All of the runs were made in random order. Data for two flow rates are as follows:

C2F6     Uniformity Observation
Flow 1      2      3      4     5      6

125   2.7   4.6 2.6   3.0   3.2   3.8

200   4.6   3.4   2.9   3.5   4.1   5.1

a) Does C2F6 flow rate affect average etch uniformity? use a=0.05

b) What is the P-value for the test in part (a)

c)Does the C2F6 affect the wafer-to-wafer variability in each uniformity? use a0.05

d) Draw box plots to assist in the interpretation of the data from this experiment

“3. Would these conditions apply to all fungal growth? Why or why not?”

“4. How would changing the type of bread (fresh from a bakery, no preservatives vs. prepackaged with preservatives) affect the results? Describe an experiment that would test your hypothesis.”

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“5. How would changing the incubation temperature of the bags affect the results? Describe an experiment that would test your hypothesis.”

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“6. Look up the pH of lemon juice and vinegar. Based on your results and your knowledge of favorable environmental conditions for fungal growth, what can you conclude about the effect of pH on growth? How would making the pH more basic affect growth?”

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“7. What is the source of the mold that grew on the samples?”

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1. The experimental results in the table below represent real values from an experiment on the cat soleus muscle. For our purposes we will assume the muscle weighs 4 grams and is shaped like a cylinder that is 1 cm² in cross-sectional area.

2. a Draw and label the force-velocity curve for this muscle in the graph on the right. Make sure you label and scale all axes.

2b. Draw a second line that is the power-velocity curve. (Hint: watch your units here!!)

Please answer and draw both curves and give explanation. Will give great review.

Answer the following questions thoroughly. Use correct grammar and punctuation.

1) A student observes the following spinner and claims that the color red has the highest probability of appearing, since there are two red areas on the spinner. What is your reply? Your answers should include facts, rules, any definitions necessary to explain why the student is correct or incorrect.

2) In class, an experiment of flipping a coin is performed.

Pretend that you are introducing the concept of probability and introducing the terms 1) experiment, 2) outcomes, 3)sample space, 4) theoretical probability, and 5) empirical probability. Explain these terms, as if you were speaking to a 5th grade class, as if they knew nothing about probability. You will need to tell the class what each term , 1-5, is represented by in this particular example. Use correct grammar and punctuation.

a) Is there evidence to support the claim that cotton content affects the mean tensile strength at a = 0.05?

b) Is there a significance difference in a percent conent among the groups? What would be the percent content that you would recommend? Justify your answer

Use R-Studio to plot this PAIRED SAMPLES T-TEST

To motivate citizens to conserve gasoline, the government is considering mounting a nationwide conservation campaign. However, before doing so on a national level, it decides to conduct an experiment to evaluate the effectiveness of the campaign. For the experiment, the conservation campaign is conducted in a small but representative geographical area. Twelve families are randomly selected from the area, and the amount of gasoline they use is monitored for 1 month before the advertising campaign and for 1 month after the campaign. The following data are collected:

Benzene is a known human carcinogen. The boiling point of benzene is 80. °C (reference 1).

a) Research online to find the short term exposure limit (STEL) for benzene. What does the STEL mean?

b) A friend is planning to do an experiment with liquid benzene at 21 °C on the open bench top in a small   (18 m3 ) poorly ventilated room (i.e. consider the room to be a closed system for this question). Convert the STEL to vapour pressure for this room.

c) Calculate the theoretical vapour pressure of benzene inside the room at 21 °C. Use your data to explain to your friend why he can or cannot do the experiment.

d) Fully explain why the following equation (derived from the ideal gas law) cannot be used to calculate the vapour pressure/temperature data at another temperature/pressure. P1/T1 = P2/T2

Thanks!

Answer the following questions thoroughly. Use correct grammar and punctuation.

1) A student observes the following spinner and claims that the color red has the highest probability of appearing, since there are two red areas on the spinner. What is your reply? Your answers should include facts, rules, any definitions necessary to explain why the student is correct or incorrect.

2) In class, an experiment of flipping a coin is performed.

Pretend that you are introducing the concept of probability and introducing the terms 1) experiment, 2) outcomes, 3)sample space, 4) theoretical probability, and 5) empirical probability. Explain these terms, as if you were speaking to a 5th grade class, as if they knew nothing about probability. You will need to tell the class what each term , 1-5, is represented by in this particular example. Use correct grammar and punctuation.