As the new manager of a small convenience store, you want to understand the shopping patterns of your customers. You randomly sample 20 purchases from yesterday’s records. Here is the data in S. dollars. 39.05 2.73 32.92 47.51 37.91 34.35 64.48 51.96 56.95 81.58 47.80 11.72 21.57 40.83 38.24 32.98 75.16 74.30 47.54 65.62 Using a calculator, find the sample mean and sample standard deviation of these What purchase amount is 2.5 standard deviations below the mean? A particular purchase at your store has a ?-score of −0.73. What was the dollar amount of that purchase?
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.
- As the new manager of a small convenience store, you want to understand the shopping patterns of your customers. You randomly sample 20 purchases from yesterday’s records. Here is the data in S. dollars.
|
39.05 |
2.73 |
32.92 |
47.51 |
37.91 |
34.35 |
64.48 |
51.96 |
56.95 |
81.58 |
|
47.80 |
11.72 |
21.57 |
40.83 |
38.24 |
32.98 |
75.16 |
74.30 |
47.54 |
65.62 |
- Using a calculator, find the sample mean and sample standard deviation of these
- What purchase amount is 2.5 standard deviations below the mean?
- A particular purchase at your store has a ?-score of −0.73. What was the dollar amount of that purchase?
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