Normality is a measure of concentration in chemistry, defined as the number of gram equivalents of solute per liter of solution. It is particularly useful in acid-base titrations, redox reactions, and precipitation processes. The formula for calculating normality (N) is: ...
In a one-sample t-test, we take a small sample of data from a large population. For example, a small sample of 10 students from a large population of 150 students. The formula then takes the average of a small sample and compares it with the average of the population to check if the...
1. Sample size and normality The larger the sample size, the more closely the sampling distribution will follow anormal distribution. When the sample size is small, the sampling distribution of the mean is sometimes non-normal. That’s because the central limit theorem only holds true when the...
Normality - Each population is normally distributed. The F-test for equality of variances is highly sensitive to deviations from normality. Independence - The two samples are independent of each other. Random Sampling - The observations in each group are randomly sampled from their respective populati...
The empirical rule is often used in statistics for forecasting final outcomes. After calculating thestandard deviationand before collecting complete data, this rule can be used as a rough estimate of the outcome of the impending data to be collected and analyzed. ...
The empirical rule is also a simplenormality test. Based on the probabilities, you know that 99.7% of all observations should fall within three standard deviations from the mean. Therefore, only 100 – 99.7 = 0.3% should be outside the limit for a normal distribution. If too many values fa...
Let’s close this post by calculating the results for a Z test by hand! Suppose we randomly sampled subjects from an honors program. We want to determine whether their mean IQ score differs from the general population. The general population’s IQ scores are defined as having a mean of 100...
For calculating disease activity index (DAI), we recorded body weight loss, stool consistency and rec- tal bleeding scores. For body weight loss, 0 points for no weight loss, weight losses in the ranges between 1 and 5%, 6 and 10%, 11 and 20%, and beyond thereaf- ter from baseline ...
No specific therapeutic medications for IBS-D have been found. Published clinical trials suggest that Chinese herbal formula Tongxie Yaofang (TXYF) for IBS-D may be effective. However, high-quality clinical evidence supporting its use in IBS-D is still lacking. This trial aims to evaluate the...
To perform a chi-square goodness of fit test, follow these five steps (the first two steps have already been completed for the dog food example): Step 1: Calculate the expected frequencies Sometimes, calculating the expected frequencies is the most difficult step. Think carefully about which exp...