Hinton 1995

With what assumption does Hinton open the last paragraph on p. 78? Hinton is looking for size differences and an accurate way to test them. The assumption is that all sample means can be compared with the standard error of difference.

What is the null hypothesis? The null hypothesis, or N₀, is a hypothesis which the researcher tries to disprove or reject the initial hypothesis, or N₁.

What statistical tool do we use to determine “what differences would we expect between two samples simply by chance alone”? Use the distribution of differences between two sample means. The standard deviation is a statistic that tells you how tightly all the various examples are clustered around the mean in a set of data. ST is raw data minus the mean, squared (variance), totaled, divided by the quantity and rooted.

What is a t-test? ‘T’ tests are the test statistics used to determine hypothesis. The method uses a small sample and analyzes the resulting mean.

What are the assumptions of the t-test? Statistical tests of the t-test assume that for accuracy, certain conditions are being met.

Summarize the first example given:

1. What question is this teacher asking (predicting)? The teacher believed that her young students worked more effectively in the morning than in the afternoon.

2. What data does she collect to test her research hypothesis? Eight math questions.

3. Is this a one-tailed test or a two-tailed test? When using a two-tailed test, you are testing for the possibility of the relationship in both directions of the bell curve, and a one tailed test looks only at one direction. The test consists of a morning and afternoon sampling of all subjects, and is a one-tailed test as the prediction was that the children would perform better in the morning.

4. What is the statistical null hypothesis? A quantifiable aspect of the null hypothesis.

5. What level of significance did the teacher choose? P-0.05.

6. Is the t-statistic greater than or less than the t for that level of significance? The calculated value of “T” is 2.65. The table value of “T”=1.895 is less.

7. Does she accept or reject her statistical null hypothesis? She rejects the null hypothesis.

8. Does she accept or reject her research hypothesis? She accepted it.

Summarize the second example given:

1. What is the research hypothesis? Will a new sleeping pill have a different effect on men and women?

2. What data were collected to test the research hypothesis? The number of extra hours slept.

3. Is this a one-tailed test or a two-tailed test? Two-tailed.

4. What is the statistical null hypothesis? 12

5. What level of significance was chosen? P=0.05

6. Is the t-statistic greater than or less than the t for that level of significance? The calculated value of “T” is 1.82. The table value of “T”=2.179 is more.

7. Should you accept or reject the statistical null hypothesis? Accept.

8. Should you accept or reject the research hypothesis? Reject.

What question does the t-test answer, in general? The t-test compares two groups. It calculates the differences, and analyzes that list of differences based on the assumption that the differences in the entire population follow a bell curve distribution.

What question do you think you’ll use as part of the t-test to explore in your research project? Are there total mass changes in nucella lamellosa based on specimens from False Bay to the ones at the Land Bank?