For 15 students at a secondary-school canteen, the following sales amounts arranged in ascending order of magnitude are observed: $10, 10, 12, 12, 12, 13, 14, 15, 19, 20, 25, 27,29, 30, 34. Determine the (i) mean (ii) median (iii) standard deviation for these sales amounts
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.
For 15 students at a secondary-school canteen, the following sales amounts arranged in
ascending order of magnitude are observed: $10, 10, 12, 12, 12, 13, 14, 15, 19, 20, 25, 27,29, 30, 34.
Determine the
(i) mean
(ii)
(iii) standard deviation for these sales amounts
(iv) second decile
(v) 40th percentile point for these sales amounts
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