LS23L Week 1 - Scientific Method and the MIT

Mean

A form of descriptive statistics. Arithmetic average (add them all up and divide by the number of numbers).

Descriptive Statistics

E.g. mean, standard deviation, and mode. Describe the pattern and distribution of measurements.

Inferential Statistics

E.g. t-test. Used to assess whether two samples are coming from the same population.

Population

The entire collection of measurements on which the researcher intends to draw conclusions

Memory Interference Test (MIT)

A computer program that uses either visual or auditory cues to test the subject's memory. In terms of test performance, one can compare two different parameters: number of correct responses or average response time.

Mode

A form of descriptive statistics. Measurement of relatively great concentrations in a set of data (most commonly appearing number).

Median

A form of descriptive statistics. The measurement located at the middle of the ordered set of data.

The Falsificationist Procedure

A way of increasing the power of conclusions made by the hypothetico-deductive approach. It involves taking the hypothesis (H1) and creating a null hypothesis (H0) that predicts no effect or no difference between two or more tested samples. The reason for doing this is that the hypotheses can be disproved much more easily than they can be proved.

Which of the following would be an appropriate null hypothesis to test the whether the newest cholesterol lowering drug, Cholesterol-B-Gone, is effective for men of age 35-50? Select one: a. Men of age 35-50 who take Cholesterol-B-Gone every day for three months will experience no change in their cholesterol levels. b. Men of age 35-50 who take Cholesterol-B-Gone every day for three months will see an increase in their cholesterol level. c. Men of age 35-50 who do not take Cholesterol-B-Gone once a day for three months will experience no change in their cholesterol levels. d. Men of age 35-50 who do not take Cholesterol-B-Gone once a day for three months will experience a decrease in their cholesterol levels. e. Men of age 35-50 who take Cholesterol-B-Gone once a day for three months will experience a decrease in their cholesterol levels.

A. Men of age 35-50 who take Cholesterol-B-Gone every day for three months will experience no change in their cholesterol levels.

According to the Research Information Sheet, possible risks you assume while participating in the Memory Interference Test (MIT) include: Select one: a. All of these b. Fatigue/tiredness c. Broken bones d. None of these e. Head injuries

B. Fatigue/tiredness

Choose the false statement concerning information from the Research Information Sheet. Select one: a. Your specific scores on the test will not be accessible to you or anyone else. b. The database will provide you with demographic information about all subgroups as long as they contain at least 2 people c. You may opt out of answering any question on the pre-test questionnaire. d. All demographic information and performance results will be kept strictly confidential. e. The purpose of this study is to build a database with which to practice experimental design.

B. It will only show you information about subgroups as long as they contain at least 50 people.

In the Memory Interference Test (MIT), if the p value is greater than 0.05, then Select one: a. The t-test value is less than .05. b. The difference between the experimental and control groups is statistically insignificant. c. It can be concluded that one group performed significantly better than the other group. d. The null hypothesis is rejected. e. The degrees of freedom is greater than 500.

B. The difference between the experimental and control groups is statistically insignificant.

What is the statistical test that will be used in this week's lab? Select one: a. Rank-sum test b. Kruskal-Wallis test c. Student's t-test d. No statistical test will be run on this data e. Chi-square test

C. Student's T-Test

t-Test

Determines the difference between two samples by comparing their means while taking into account their variances.

Which of the following statements is correct? Select one: a. The larger the p-value, the stronger the evidence is against the null hypothesis. b. The smaller the p-value, the stronger the evidence for the null hypothesis. c. A large p-value indicates that the data is consistent with the alternative hypothesis. d. The p-value indicates the probability that the alternative hypothesis is true. e. An extremely small p-value indicates that there is a difference between the two data sets being compared.

E. An extremely small p-value indicates that there is a difference between the two data sets being compared.

According to the Research Information Sheet, you will be paid for participating in this study. Select one: True False

False

Part of the MIT is taken using pen and paper. Select one: True False

False

Standard Deviation

Measure of variation around the mean.

Hypothetico-Deductive Approach

Proposed by Karl Popper. It begins with observations of events or patterns, followed by suggestions for the general causes and nature of the observed events and patterns. Next, the approach requires a specific hypothesis that must be tested (either by carrying out appropriate experiments or making specific observations). The results are measured and tested statistically, allowing us to conclude whether our hypothesis was supported and deduce something about the phenomenon. If the hypothesis was supported, we continue research to support hypothesis. If it was rejected, develop new theory.

Sample

The set of measurements actually made (ex. sampling daily dietary calories of one thousand individuals from each capital of a South American country)

P-Value

While a t-value only tells us how different two groups are, it doesn't tell us how significant this difference is. Therefore, the t-value must be converted to a p-value. If the p-value is under 5% (the significance level), it means that there is less than a 5% chance to have made a mistake by rejecting the null hpothesis. If you get a p-value of 0.19, this means that there is a 19% chance that your groups are not statistically different.

A scientist got a p-value of 0.039 when testing his data. Assuming there was a small difference between the means in the two groups of his hypothesis, will these results give a significant difference? Select one: a. No, because the p-value is less than 0.05. b. Yes, because the p-value is less than 0.05. c. Yes, because there is a small difference between the means. d. There is not enough information given in the problem to answer this question. e. No, because there is a small difference between the means.

b. Yes, because the p-value is less than 0.05