Chapter 18: Study Design And Data Handling

Question 1

The research question is usually expressed as a(n):
A- Probability statistic
B- Hypothesis
C- Discussion item
D- Data collection strategy

Answer 1

B- Hypothesis

Question 2

A study attempts to determine if suing treats, such as chocolate chips, elicits a desired behavior in rats of moving through a tunnel to a new cage and helps the rats learn the behavior quicker. What is the independent variable?
A- The treats
B- The tunnel
C- The observed behavior
D- The number of rats using the tunnel

Answer 2

A- The treats

Question 3

True or False
In a scientific study, the control group is the group receiving the experimental treatment.

Answer 3

False

Question 4

True or False
In any scientific study, the goal is to include as many animals as possible in each group.

Answer 4

False

Question 5

True or False
In statistics, the p value is the opposite of the confidence level.

Answer 5

True

Question 6

What is the variable that is measured during the study?

Answer 6

Dependent variable

Question 7

What is the variable that is manipulated by the investigator?

Answer 7

Independent variable

Question 8

What do we call the similar group of animals that does not receive the experimental treatment?

Answer 8

Control group

Question 9

What do we call the animals that receive the experimental treatment?

Answer 9

Treatment group

Question 10

Name a statistical method that helps control variables by eliminating personal bias from the study.

Answer 10

Randomization

Question 11

If two sets of rat weight data are found to be significantly different at a p-value of 0.05, which of the following interpretations of the results is the most accurate?
A- There is a 0.05 g difference between the average weight of the art in group A and group B
B- There is only a 5% chance or better that the weights if the rats in the two groups are different.
C- There is at least 95% probability that the weights of the rats from group A are different from the weight of the rats in group B.
D- The mean of the weights of group A rats differs from the mean of the weights of rats in group B by a standard deviation equal to 0.05.

Answer 11

C- There is at least 95% probability that the weights of the rats from group A are different from the weight of the rats in group B.

Question 12

True or False
For a sample that has a normal distribution, 95% of the data points will fall within +/- 2 SD.

Answer 12

True

Question 13

What is the difference between the confidence level and the p-value?
A- An index of certainty that the difference is due to the experimental treatment
B- The probability that the observed difference happened by chance
C- The measure of the dispersion of data
D- The probability that the difference is due to normal variation

Answer 13

A- An index of certainty that the difference is due to the experimental treatment

Question 14

What factor is controlled by randomization?
A- Bias
B- Power
C- Null hypothesis
D- p-value

Answer 14

A- Bias

Question 15

Explain the difference between an experimental and a null hypothesis.

Answer 15

The experimental hypothesis is a prediction of the results of a study; it is a statement of the answer the investigator expects to find to the research question. The null hypothesis states that there is no difference between the means of the two groups; that is, the treatment has no effect on the dependent variable

Question 16

In a normal distribution, what percentage of measurements fall between the mean and plus or minus 1 standard deviation?

Answer 16

68%

Question 17

In a normal distribution, what percentage of measurements fall between the mean and plus or minus 2 standard deviations?

Answer 17

95%

Question 18

In a normal distribution, what percentage of measurements fall between the mean and plus or minus 3 standard deviations?

Answer 18

99%

Question 19

What term means anything that can potentially affect the results of the study?

Answer 19

Variable

Question 20

What term means index of certainty?

Answer 20

Confidence level

Question 21

What term means measure of the dispersion of data?

Answer 21

Standard deviation

Question 22

What term means the probability that the observed difference happened by chance alone?

Answer 22

P-Value

Question 23

What term means a statement that there is no difference between the means of the two groups?

Answer 23

Null hypothesis

Question 24

What term means the number of experimental units in a group?

Answer 24

Sample size