A drug company claims that their products’ contaminations never vary by more than 2%. Sample of 5 specimens were tested and the percentages of the purities are recorded as Observation no. 1 2 3 4 5 Percentages (%) 98.6 97.2 98.9 97.7 97.9 a. Do the sample data have enough proof to oppose the manufacturer’s claim? (HINT: take the range of 2% equal 4σ.) b. Find a 90% confidence interval for σ2.
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
A drug company claims that their products’ contaminations never vary by more than 2%. Sample of 5 specimens were tested and the percentages of the purities are recorded as
|
Observation no. |
1 |
2 |
3 |
4 |
5 |
|
Percentages (%) |
98.6 |
97.2 |
98.9 |
97.7 |
97.9 |
a. Do the sample data have enough proof to oppose the manufacturer’s claim? (HINT: take the
b. Find a 90% confidence interval for σ2.
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