Final - Lab 2

Question 1

If you are asked to pipet 590 microliters of colored water, which pipetter would you use and what is the proper setting in each volumeter window? (top, middle, bottom)

Answer 1

p1000 (0,5,9)

Question 2

Which of the following is critical in designing a scientific experiment to test memory in chimpanzees?

a. The experimenter should control for lurking variables by specifying standard conditions (i.e. room temperature).
b. there is no need for repeated trials because chimpanzees would perform similarly on subsequent memory tests
c. the sample size should be small as possible so the data can be analyzed effectively
d. only chimpanzees with intermediate weights should be included so that no extreme results are observed
e. the experimenter’s objective is to obtain data with a p-value with the highest possible value

Answer 2

a. The experimenter should control for lurking variables by specifying standard conditions (i.e. room temperature).

Question 3

1 microgram (μg) is equal to how many milligrams (mg)?

Answer 3

0.001

Question 4

what pipette should be used for 9.7 microliters (ul)

Answer 4

p20

Question 5

Which of the following techniques for handling a pipetter is INCORRECT:

b. When drawing up the sample liquid into the pipet tip make sure that you slowly release the pushbutton so as to prevent any air bubbles from forming.
c. A different disposable polyprolene tip should be used when pipetting different solutions so as to ensure no cross contamination between samples.
d. When releasing the liquid, you must first press the pushbutton to the first stop, then to the second stop so as to expel any remaining liquid.
e. You must be sure to press the pushbutton to the first positive stop before placing the tip of the pipet into the sample liquid.

Answer 5

All of these techniques are CORRECT.

Question 6

In a bimodal distribution of data, you would have:

Answer 6

b. Two modes, one mean, and one median

Question 7

In a recent study, scientists proposed the following hypothesis: "Consumption of Omega-3 fatty acid can reduce the size of cancerous tumors." The following hypothesis was tested. A sample of 500 rats with tumors was collected. Within this sample size, 250 rats were feed with omega-3 (Group 1) while the remaining 250 rats were not (Group 2). After one month of periodically feeding Group 1 with Omega-3 fatty acid, rat autopsies were taken for both groups. The average changes of tumor size were measure and recorded.
Average Change of Tumor Size
Group 1: -0.124 g
Group 2: -0.112 g
Degrees of Freedom: 498
T-test: 1.75
P-value: 0.08
Based on the results from the experiment, which of the following is the best conclusion?

Answer 7

Consumption of Omega-3 fatty acid has no statistical effect on decreasing the size of previous cancerous tumors.

Question 8

A null hypothesis states that the different between 8 hours of sleep has no effect on the # of pictures a student will remember during a PMIT. Examining the MIT database, an extremely small t-value of 0.1611 is found. This t-value is much smaller than the smallest t-value on the chart for p-value reference. From this info we can:

a) reject null because of the p-value obtained
b) accept null because the p-value obtained was statistically significant
c) reject null because the data obtained is statistically significant
d) accept null because the p-value obtained shows that the difference between the two groups being tested is not statistically significant

Answer 8

d) accept null because the p-value obtained shows that the difference between the two groups being tested is not statistically significant

Question 9

In a series of experiments testing effect of caffeine on goldfish metabolism, p-value of 0.28 was found.
a) caffeine did affect and null
cannot be rejected
b) caffeine did not affect and null is rejected
c) caffeine did not affect and null cannot be rejected
d) there is not enough data
e) caffeine did affect and and null is rejected

Answer 9

c) caffeine did not affect and null cannot be rejected

Question 10

A student is quickly pipetting 129ul water and observes many bubbles in the tip. You as the second student demonstrate the correct order of steps:1. In order to prevent bubbles, slowly let go off your thumb and Release the pushbutton to aspirate. 2. Choose the correct pipette p200 and the correct tip to aspirate the correct amount of 129ul. 3. Push the pushbutton to the first stop before inserting the tip into the solution, and then put the tip in the solution tube.4. Dial the volume on the adjustment ring by first over dial the volume, and return to the correct amount of 129ul.5. Push the pushbutton to the first stop, raise the tip above the liquid, and press it harder to the second step to discard 129ul.6. Press the ejector to discard the tip.
Choose one answer.
a. 2, 1, 5, 3, 4, 6
b. 2, 4, 3, 1, 5, 6
c. 6, 5, 4, 2, 3, 1
d. 2, 5, 4, 3, 1, 6

Answer 10

b. 2, 4, 3, 1, 5, 6