A sample of 20 pages was taken from a Yellow Pages (yp.com) business directory. On each page, the mean area devoted to display ads was measured (a display ad is a large block of multicolored illustrations, maps, and text). The data (in square millimeters) are shown below: 0 260 356 403 536 0 268 369 428 536 268 396 469 536 162 338 403 536 536 130 Click here for the Excel Data File (a) Construct a 95% confidence interval for the true mean. (Round your answers to 2 decimal places.) The 95% confidence interval is from to . (b) What sample size would be needed to obtain an error of ±20 square millimeters with 95% confidence? (Enter your answer as a whole number (no decimals). Use a z-value taken to 3 decimal places in your calculations.)
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 sample of 20 pages was taken from a Yellow Pages (yp.com) business directory. On each page, the
| 0 | 260 | 356 | 403 | 536 | 0 | 268 | 369 | 428 | 536 |
| 268 | 396 | 469 | 536 | 162 | 338 | 403 | 536 | 536 | 130 |
Click here for the Excel Data File
(a) Construct a 95% confidence interval for the true mean. (Round your answers to 2 decimal places.)
The 95% confidence interval is from to .
(b) What
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