Probability: The T-Test Statistic

We conduct an independent sample t-test using Excel, and obtain the following output (see t-test-height)

at the beginning of this study, due to the short period of time between testing. However,

All the p-values are greater than 0.05, therefore there is a statistical difference between each transect.

1. Are any of the lab values in Table 1 out of normal range? Do you see some that are too high or too

e. Now for the same data, Test the hypothesis that the median value of the difference in weights before and after the dieting programme is non-existent. What is the name of this test? Also state what the symmetric CI for the median of the difference would be.

t = −3.15 describes the difference between women and men for what variable in this study? Is this value significant? Provide a rationale for your answer.

If the total sample size is over 15, two sample t tests are safe if there are no

Reporting t values- when you have already reported p values- is not necessary and can cause confusion.

Note: the program we used on this worksheet said the results were not significant, but then in statistical notion it had “p < 0.05”. That is confusing because I believe it should be “p >

Consider the following scenario in answering questions 5 through 7. In an article appearing in Today’s Health a writer states that the average number of calories in a serving of popcorn is 75. To determine if the average number of calories in a serving of popcorn is different from 75, a nutritionist selected a random sample of 20 servings of popcorn and computed the sample mean number of calories per serving to be 78 with a sample standard deviation of 7.

It tells that the t-statistic with 97 degrees of freedom was 2.14, and the corresponding p-value was less than .05, specifically around 0.035. Therefore, it is appropriate to conclude the research study was statistically significant.

However, treatment four, 0.1296 (±0.608), represents that the mean was extraneous from what it should be (Table 1). The t-tests show how different the mean is in each treatment.

The next table shows the results of this independent t-test. At the .05 significance level, can we conclude

We conduct an independent sample t-test using Excel, and obtain the following output (see sheet T-TEST)

With a P-value of 0.00, we have a strong level of significance. No additional information is needed to ensure that the data given is accurate.