Calculate Variance, Standard deviation, and Coefficient of Variation (CV) of the students heights.
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.
Let X be the height of the student.
A |
179 |
174 |
156 |
171 |
170 |
165 |
170 |
157 |
155 |
157 |
177 |
172 |
154 |
155 |
158 |
170 |
174 |
170 |
154 |
172 |
164 |
173 |
164 |
172 |
173 |
150 |
150 |
160 |
150 |
166 |
It is required to obtained the variance, standard deviation, and coefficient of variance.
The formula for variance (σ2) is
where
Therefore,
X | ||
179 | 14.6 | 213.16 |
174 | 9.6 | 92.16 |
156 | -8.4 | 70.56 |
171 | 6.6 | 43.56 |
170 | 5.6 | 31.36 |
165 | 0.6 | 0.36 |
170 | 5.6 | 31.36 |
157 | -7.4 | 54.76 |
155 | -9.4 | 88.36 |
157 | -7.4 | 54.76 |
177 | 12.6 | 158.76 |
172 | 7.6 | 57.76 |
154 | -10.4 | 108.16 |
155 | -9.4 | 88.36 |
158 | -6.4 | 40.96 |
170 | 5.6 | 31.36 |
174 | 9.6 | 92.16 |
170 | 5.6 | 31.36 |
154 | -10.4 | 108.16 |
172 | 7.6 | 57.76 |
164 | -0.4 | 0.16 |
173 | 8.6 | 73.96 |
164 | -0.4 | 0.16 |
172 | 7.6 | 57.76 |
173 | 8.6 | 73.96 |
150 | -14.4 | 207.36 |
150 | -14.4 | 207.36 |
160 | -4.4 | 19.36 |
150 | -14.4 | 207.36 |
166 | 1.6 | 2.56 |
=
= 79.48966
The variance of students heights is 79.48966
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