An independent sample experiment uses 25 participants in one group and 30 participants in the second group to compare the  two population means. What is the degrees of freedom used in this test ?  

a.

25

b.

24

c.

30

d.

29

Draw an experiment circuit to produce and measure a 5 kA peak lightning impulse current. In the test circuit, determine the methods of measuring the pulse current, determining the element values and properties according to the current to be measured. Describe one of the methods.

How does the magnitude, sign, and rate of change of the magnetic flux, and the number of turns in the secondary affect the induced emf? In an experiment of Moving a permanent magnet AND an electromagnet in and out of a pickup coil and seeing the brightness or voltage.

Relating to Faraday's Law

These quistion related to Oxidase Assay for Respiration and Catalase Assay experiment

1.In the clinical (real-world) setting, what is the main objective of performing laboratory tests such as the oxidase or catalase assays?

2.Some very important pathogens are positive for the oxidase test. Use your text or the Internet to find one such example.

3.A student performing the Experiment 2 of this lab set up a positive control with a known catalase-positive bacterium. However, he had no remaining hydrogen peroxide in his lab kit supplies so he used some that he had in his home medicine cabinet.   No bubbles were produced after the addition of the hydrogen peroxide even though the organism is catalase positive. What explanation can you give for this

A double-slit experiment is set up using red light (λ = 711 nm). A first order bright fringe is seen at a given location on a screen.

1)What wavelength of visible light (between 380 nm and 750 nm) would produce a dark fringe at the identical location on the screen?

λ =

2) A new experiment is created with the screen at a distance of 1.9 m from the slits (with spacing 0.11 mm). What is the distance between the second order bright fringe of light with λ = 698 nm and the third order bright fringe of light with λ = 409 nm? (Give the absolute value of the smallest possible distance between these two fringes: the distance between bright fringes on the same side of the central bright fringe.)

|x| =

Jordan is doing a science fair project on the effects of music on the growth of tomatoes. He has two tomato plants, Plant A and Plant B, that he grows in a window and gives the same amount of water. Plant A is exposed to classical music using headphones attached to the soil. Throughout the growth period, Jordan counts the number of tomatoes produced by each plant.

Plant A = 35 Tomatoes | Plant B = 55 Tomatoes

1) What is the control group?
2) What is the independent variable?
3) What is the dependent variable?
4) What should Jordan’s conclusion be? Write this in a complete sentence!
5) Jordan needs to repeat the experiment, but his teacher says that he needs to improve his design. In his second experiment, what should he do different.

A crossover trial is a type of experiment used to compare two drugs. Subjects take one drug for a period of time, then switch to another. The responses of the subjects are then compared using matched-pair methods. In an experiment to compare two pain relievers, seven subjects took one pain reliever for two weeks, then switched to the other. They rated their pain level from 1 to 10, with larger numbers representing higher levels of pain. Can you conclude that the mean pain level is less with drug B? Use significance level 0.10. (Paired samples).

During Part I of the water Analysis series, you prepared a Stock solution of Nitrate ion containing 250.0 mg N/L. In the second part of this experiment, you will use this Stock solution to prepare four Standard solutions to be used to make a calibration plot. As described in the background information for this experiment, the concentration of Nitrogen in these standards should be between 1 and 10 mg N /L.

A.) Describe HOW you are going to prepare a standard solution which must contain 8.0 mg N/L. Assume you are going to use a 250-mL volumetric flask for this preparation. Be sure to include necessary CALCULATIONS !

B.) Another one of the standard solutions should have the concentration of 10.0 mg N /L. Show calculations to be used for preparation of 250.0 mL of this solution.

A 0.6972 g of impure potassium hydrogen phthalate (FW: 204.23) was dissolved in 30 mL of water and 2 drops of phenolphthalein was added. It required 24.83 mL of 0.1097 M NaOH for complete titration.

a. how many moles of acid are present?

b. how would the titration be affected if you used 0.8786 g of KHP?

c. if you added 27.75 mL of NaOH instead of 25.83 mL, what would you expect to see? Note, this question does not involve a calculation, rather it is referring to your qualitative observations of the experiment.

d. when setting up their experiment, a student discovered that the solution in their flask turned bright pink upon adding 2 drops of the indicator, even before beginning the titration. what do you suspect was the mistake the student made?